FCOM: will it completely alter the gameplay - and especially the questlines, so I for instance:
- won't be able to complete the game at level 1.
- won't be able to hold high ranks at the guilds at level 1.
- won't be able to beat everyone at the arena.
- ...and is the MOD build logically, so the easier quest are found first (or at least give some sort of hint to the required level for the quest).
or does the MOD just make gameplay more difficult but basically it's still the same.
Dunno. Even with OOO it's still a skill-based game, right? And unless you add certain levelling mods you're not forced to level. Basic OOO does not affect the player levelling system - I strongly recommend you add a good levelling mod or two. But I can say, from what I've read about OOO, that you wouldn't be able to do any of those things at level 1 with your starting skills and gear. Probably the higher level monsters do enough damage that you'd never be able to survive with your starting health, so yeah, you could say you'd have to level to finish a lot of the content. Although with high Conjuration and Illusion.and the more powerful magic system..yeah, maybe you wouldn't really have to level.
I've never tried OOO because I don't need Oblvion to be more like Morrowind. One of the biggest downsides to Morrowind was the way levelling was handled. You didn't get more difficult mobs. You got more of them. Chewing through 7 cliffracers patiently waiting in line ?!? to be slaughtered wasn't my idea of fun. Fortunately, I believe OOO does it better.
Mara