You have problems, Mam.

*there really needs to be a gender off to the side*

Anyways, to keep this topic on topic, my biggest fear is that they rush the game whilst putting in things according to our complaints therefore causing a unfinished launch.

my biggest fear is of snakes, and little rodents.

My biggest fear is that they will bring back the open world. The open world was disastrous for my gameplay. By having the whole neighbourhood run together, it meant that you could only control one saved family per neighbourhood, which is a huge letdown even from the days of TS1's 8 lots per 'hood. I just don't understand why people love the open world so much. It destroyed everything good about the sims, and offered very little in retribution:

The Good:
1 Townies age along with your sims.
2 Your sims can leave their lot whenever they want.
3 There are many community lots you can go to.
4 You can watch a car drive from your sim's home to the community lot.

The Bad:
1 All the sims that you could have enjoyed playing with are reduced to townie status, resulting in a loss of control of all but your one chosen family.
2 Your sims are all over the neighbourhood, and you can only watch one of them at a time.
3 Most community lots are rabbit holes, and for those that aren't, there is nothing to do there that you can't do at home.

Seriously, almost every "good" thing about the open world, is actually a bad thing in disguise. The only thing you're left with, after you remove all the the hype that was shoved down our throats upon the game's release, is a pretty map from neighbourhood view, where you can view your entire town, and understand where your sim's home is, in relation to the other lots. And that's where you spend most of your time in TS3, instead of enjoying closeups of your sims in action - out in neighbourhood view, trying to locate your 'other' sims, which have wandered off.

Open world does not mean that you have to lose control of your sims. That is Story Progression, not open world. We could have an open world concept where your sims do nothing but sit in their houses until you play them. Open world means that your sim can walk across the world, through other lots, visit neighbors or community lots without a loading screen.

Even in a non-open world, you can only watch 1 sim at a time. In fact, it is much easier to switch between sims in various places and from other families in an open world.

Again, rabbitholes have nothing to do with open worlds. We could have restaurants and shops in an open world as we do have with mods. We could have rabbitholes in a closed world. In Sims 2, the sims went off to work to a "rabbithole" that was off-world, they disappeared. In Sims 3, then went to work in a rabbithole that was in-world. Very little difference. Either way, you could not follow them to work. We have open bars and food service places in Sims 3 and there really isn't any reason that EA didn't give us open restaurants and shops other than they did not want to do so.

So..blame your concerns on EA for not opening up restaurants and shops, not on the open world. My hope is that Sims 4 will allow us to have both. If not, it is another step backwards. I don't think I would buy the game if it continues to go backwards.

I guess that my biggest fear would be for the game to be so buggy and disfunctional that it becomes more tedious than fun to play. This is how I often feel about TS3. Just the shoddy routing system alone kills a lot of my enjoyment.

About rabbitholes: The most pressing argument for having an open world is so your sims can travel to community lots. The fact that in TS3, most of these lots were rabbitholes, is kind of a pissoff, and to me it's especially aggravating, because I was against open world in the first place, and now they've done it all for nothing. The fact that there is "very little difference" from going to work in TS2 illustrates my point - an open world was not needed for any of these rabbitholes. Each rabbithole in the world represents one feature for which an open world was completely unnecessary. If you remove those, what is left? A gym, a library, a community pool, a graveyard? All of these, except possibly the graveyard, represent pasttimes that could easily be done at home, without a loading screen, or even car travel.

About loading screens: I will not allow the pro-openworlders to take credit for eliminating the loading screens. A loading screen is nothing more than a wait time while your area is loading. In TS3 there was noticeable lag when entering a community lot, and meanwhile, the game clock continued to tick, while your screen was frozen, and the lot objects were rendering. It was faster than TS2, but that's more due to the faster game engine than the open world.

The open world absolutely means that you must lose control of your sims. Story progression entails the changes in status of your sims, such as marriage, babies, career changing, and moving from one house to another, or out of existence entirely. But this is only a small part of a sim's life. The open world causes you to lose much more than that. I do not have a problem with the concept of an open world per se, however, it's very existence causes an overturning of numerous other features that were present in earlier games, and are essential for the enjoyment of gameplay. The question of open-world vs. closed world is not just for aesthetics; the pro-openworlders generally think it is "nice" to be able move freely through the neighbourhood, but do not comprehend the magnitude of the trouble it is causing for gameplay. There is a huge difference between the relationships of sims with their neighbours in the TS2 closed world, and the open world of TS3, and I want to make that difference clear. In TS3, the family you choose is the center of your universe. The other sims in your neighbourhood, because of the open world, move forward in time, age, and progress through life all around you, while you play your one family. Your neighbours have very little importance to your game, and you have no control over what happens to them while you are not playing them. Furthermore, as they are aging alongside your sims, you never will get to play them during the same timeframe as exists for your one family. It is extremely boring to play only one family, but to switch means you give them up to the AI, and they become as meaningless to the game as your other neighbours. In TS2, your neighbourhood had many different lots, each of which could hold one family. Each family had its own saved game, where it was safe from tampering by the AI. You had full control over everything your sims did while you were playing them, and they never aged or progressed while you were playing other families. If you played each family for the same number of days, you could easily make them age at the same rate, and every family in your neighbourhood was just as important as any other. Instead of one family, you could control up to 70. As I see it, the object of the game is to try to keep your sims motives high, even as they are gradually falling over time. You also have a secondary objective of advancing your sim's career by skilling, and making family friends. This objective flowed very smoothly in TS2. In TS3, however, each time you switch families, the sim's motives reset, causing you to lose the focus of the game you were playing for that family. Furthermore, it is not uncommon for sims in other families to change jobs while you are not looking, further undermining your game progress. So, if you want to do more than just sandbox play (wandering around, interacting with random objects and people), and play the traditional 'motive-driven' game, you are restricted to one family in TS3. While the issues affecting 'other' families in TS3 (motive resets/career changes)are not always directly attributable to the open world, they could not be present in a TS2-style world, since each family is self-contained. Having an open world at all, predisposes the game to have these types of annoyances, and you can bet that if EA goes with an open world concept, they are not going to take pains to avoid them all.
Therefore, I am vehemently opposed to an open world for Sims 4.