This game work (well) yet?

In short no it is not better as far as multiplayer presence.  With the next expansion, diplomacy, it split the community with a completely seperate lobby from vanilla/entrenchment.  There are on average about 30 -40 people online by the count on diplomacy during peak hours.  There are still players but sometimes you have to wait a while to fill a game.  Trinity is vanilla packaged together with entrenchment and diplomacy so you don't have to buy the whole thing rather than just adding diplomacy.  It is in general a bit more stable with the latest patch as far as crashes or minidumps.  Balance issues remain in general(latest flavor of the month is skirantra and scramble bomber spam).  Smurfing(pros in noob clothing) still remains a problem.  If you have little in the way of stats, they will assume you are a smurf still.  They may play with you still for lack of others to be choosy from.  Best of luck if you decide to give it another whirl.

[_]-Greyfox

A patch was recently released that fixed many of the minidump and desync problems.

What Greyfox said is somewhat accurate.  The Diplomacy expansion split up the already low online multiplayer player counts.  However, you can still find games during North American prime time (say from 7-11 pm EST) and on the weekends.  There are still people out there playing Entrenchment and Regular Sins, but many of them are newer players with the pro community seeming to have mostly migrated to Diplomacy.  As a general rule, player counts for Regular/Entrenchment seem to be lower than for Diplomacy.  Diplomacy player counts during prime time seem to be about 50-60.

Anyway, you already own Entrenchment, so you should come investigate the situation for yourself.  Definitely give it another try.  On the Regular/Entrenchment server you might find that more people are on Regular Sins now.  One problem is that you'll mostly find 1v1 and 2v2 games.  You need to get Diplomacy for the 4v4s and 5v5s, which aren't nearly as frequent as they used to be.

The big issue is whether or not it's worth spending $10 on Diplomacy.  I don't know how to answer that.  It's hard to want to invest money in a game that has low online player counts and the only reason for doing it would be to be able to play with the other people who have Diplomacy.  (Diplomacy doesn't add much to the online game, it's just that most of the regular players purchased it.)

I think it's a shame that you gave up on Sins so easily.  I have been playing since March 2008 and even though the game isn't perfect, I have enjoyed hundreds of good games on both Regular and Entrenchment.  If you had resumed playing Entrenchment six months ago, it woudn't have been difficult to find 5v5's.  About two weeks after Diplomacy was released, the player counts really started to drop for some reason.

Technical issues (minidumps, desyncs, crashes) are better.  Gameplay balance is better.  But since Diplomacy, getting into a multiplayer game is a lot harder, so that aspect is much worse.  Some people believe that multiplayer is essentially dead at the moment.

As far as running into assholes who won't let you play, or will automatically boot you from games because you are new, this used to be a severe problem.  I'd say overall, with the much lower player counts, this is actually a lot better now.  A lot of the assholes have left the game (for the time being, at least), and the ones who remain seem to be so anxious to fill a game that they'll play with whoever shows up.

Some people are hoping that Diplomacy will eventually bring a resurgence of multiplayer, with new blood being injected from new players.  It remains to be seen whether this will occur or not.

The mulei-players might increase if the game was on the shelf. No-one I know will yet buy "on-Line" anything. Had to order mine in canada.