Grunker Both OT 1 and 2 are pretty formulaic in their design. Main scenarios are pretty straightforward affairs, designed in the same way. OT2 changes it up somewhat, but not to a great extent. What OT2 has, that OT1 doesn't have is "crossed paths". There are four stories where two set characters have a common scenario.
In OT2, the merchant's story is designed a bit differently, and one of the mages also has a somewhat different scenario. The thief has two objectives, and you can choose which to tackle first. Nothing major, to be honest.
What I really liked about both games, besides the shallow parts (graphics and music), was finding optional areas and bosses. In OT1, it was fun fighting the extra job bosses, and doing side quests. In OT2, it was finding all the super bosses, and doing side quests. Main stories are neither overly offensive, nor masterfully written.
I also liked playing around with the jobs, even if you will inevitably find ways to break the game, in both entries. To me, the fun is finding that stuff out on your own, but I see a lot of people who said the games are super easy, but looked online for strategies. (Main stories are very doable without much knowledge.)