There are a lot of these threads about MWS, so I would suggest digging through the forums. Anyone could leave something out that may be important to you.
Long story short, it depends. Some people think it is fixed/great, some don't. I'm not super into weddings, so even if this was the most bombproof and elaborate pack to date I would not have used it to its full potential, but I do think it makes weddings better. I also like the tea sets and all the cakes, etc. I like the small details and that is why I am content enough with MWS (but the launch state was ridiculous).
Tartosa is a nice enough world, but I do think it is somewhat overrated. Pretty, but cramped to me. Still nice to have, though. The CAS is okay, but it left some things to be desired in my opinion. All that is stuff you can check.
As for the gameplay... It really is going to depend on what you want out of your weddings. If you are looking for a tight, choreographed ceremony then you are going to have to take up a full time position as a Sim wrangler. This is pretty par for the course, though. If you just wanted more things to do at and more personal or interesting weddings, you may well be good.