Seven is easily the weakest out of all the party-based Ys games. While some boss fights are enjoyable to solve and pulling a string of flash guards consistently feels very rewarding, more often than not, they overstayed its welcome because of how deep their HP pools are. Thankfully, the story is interesting enough and the final villain reveal is pretty well-done in my opinion.
The good thing about it is that Falcom actually addressed many of the shortcomings of the party system in
Memories of Celceta. We can switch between the party members more rapidly, leveling skills makes sense and becoming less of a busywork, the item collection becoming less obnoxious and they improved area mapping and exploration significantly. Sadly, story-wise it fell short, the abruptness of its ending were making it feel like half a game, with a final villain I didn't really care about, compared with Ys Seven. I feel it has one of the worst endings Falcom ever devised, which is out of the norm for them.
Now, third time's the charm:
Lacrimosa of Dana takes everything that was good from the previous entries and making it into something truly special. It has one of the best stories out of all Ys games (If not THE best). The combat is fast and responsive as usual plus jump and double-jumps making a comeback. Bosses still has high HP, but our gears and accessories are also improved so we can melt bosses faster with a combination of the right gear plus party members' abilities. No more hugging the edges of the map to complete 100% of all areas. Itemisation and item trading is also improved since it almost eliminates the need to farm materials. Plus there's a number of activities like Raids which gives you crafting materials as rewards. The only problem I have is that (party members)
Adol can't have Dogi as part of the playable team. He only appeared as a passive team member during Raids. And finally, the music is one of the best Falcom has ever done. I'm not joking. As much as I love Trails' soundtrack or Brandish TDR/Planet Buster, VIII's OST is sublime. Highly recommended.
TLDR; to really appreciate party-based Ys games, consider playing them in release order.