Just an update of my original post.
By now I have:
- two EPs, Seasons (a must for any Sims game, I guess, though far too nudgy for my taste - but then, the whole game is too nudgy for my taste) and Get Together (I needed another world, but I was rather surprised when the first Sim my Sim encountered was Cassandra Goth; breaks the immersion).
- three kits (kits are, at least for me, the most inviting part of DLC), Cozy Bistro (really nice), Artist Studio (also nice but makes sense only if you are playing an artist; some objects are usable elsewhere, but not many) and Modern Luxe Kit: my Sims are vain and have far too much money.

Speaking of money: my TS3 tenth level bestselling writer gets 15.000 and some change once a week. My TS4 tenth level bestselling writer gets 6000 and some change EVERY DAY. This game is far too easy, and not only because of money. - It's better if you play a regular career: I made a sack sack of a man, as bland as possible, and put him in a business career, but even he had no real problems (except filling out those reports - as boring as it sounds). - Anyway, I should probably build another house for my writer but ...
Speaking of building: as clumsy as it gets. UI fills a big chunk of my screen and edge scrolling practically does not exist; I have to use WASD which I hate. Obviously a big part of the clumsiness is due to my inexperience but still. Also, original wallpapers and tiles are really boring; haven't looked around yet but I'll have to, and so ...
Speaking of mods: the few that I have so far are real game changers and there are many more to discover, an absolute must. Kudos to people making them, in spite of all the obstacles.

On the whole, I am enjoying the game far more than I did all those years ago: I can make Sims' stories complicated enough to become interesting. I'll have to teach myself how to make the game work like TS2 (with MCCC; I found tutorials for that) and then it will, hopefully, become even more interesting. I think I am done with buying DLCs, though; I have what I really wanted and other games are coming along, to say nothing of TS2 and TS3.

ETA: Went on a downloading spree, mostly here on MTS (except for some mods) and only building stuff (+ a modern hot tub) so far. A lot of work but really worth it.

The last update, at least for quite a while. Bought two more items:
- Spa Day: I wondered about this one for quite a while - seemed too expensive, even on sale, but it turned out to be quite good. Lots of great build stuff and items my Sims love using at home. Yoga mat is, of course, beneath the dignity of some: my bland businessman would not look at it. He prefers sitting at his computer and getting fatter and fatter.
- Comfy Gamer: the base items, so to speak, are great, but there is also a lot of other stuff that is usable in any context. It shows what happens when a real gamer gets hold of the game.

I downloaded even more mods and survived my first EA update. It turns out that the mods I appreciate the most are the "small" tuning ones, like the one that makes your Sims change from winter clothing when they enter a building (LittleMsSam is the master in this department); also, some great career mods. If I have a problem or a wish I first look at the mods and in most cases I will find what I want.