As someone who supported all Sacred products and played them for thousands of hours - I can tell you that the shoulder perspective in Sacred 2 was a terrible thing in every aspect.
It didn't even work well with the kind of action-combat sacred offered and would often leave you disoriented in certain lategame areas when cavewalls and obstacles where a thing. Targeting a creature on the other side of some vegetation or a wall? Impossible. And don't forget there's a massive difference between a realtime arpg and a tactical multicharacter turnbased CRPG where that kind of things happen more frequently.
I kinda liked it, but then again I'm one of the seemingly few people who liked Morrowind's fog and didn't turn it off when I installed the Morrowind Graphics Extender. In fact I liked it so much I added fogging to Oblivion too.
But yeah, I take your point that it wasn't ideal in every situation; I just liked to use it periodically as I find isometric slightly disorienting if I use it for extended periods.
There's a reason even the terrible third game; Sacred-imgonnapuke-3 didn't feature a similar camera as in 2.
I never had the pleasure. I read what other people had to say about Sacred 3 and decided that some treasures are best left buried.
