Yes, 2-3 levels *should* be noticable. I really don't want the modern RPG/MMO-esque system of like 100 levels where being level 50 or 60 is pretty much inseperatable. What's wrong with the good old system of old RPG's where leveling was interesting, progressive and a true reward than having to need to fist-feed "level up cookies" every 30m to keep the gamer interested, but in doing so make leveling a meaningless pointless and utterly useless mechanic devoid of it's intention?

It reminds me of:

Pre-PoE Release: "12 levels is too low. Make it atleast 30 or so. You can't expect people to just get 11 level ups in a 60 hour game. Leveling would be just too slow, too long playing without leveling"
... then ...
Post-PoE Release: "Yeeeeah, leveling goes way too fast. You should really cut XP progression by like 50%, that would make the game much better!"

Also I *totally* miss going to hell and being pummelled to death if not suitable suited rather than 'modern RPG's having the true Demon of Hell being level 2 just to suit you and "we can't have people not instantly move all around this gigantic map"...
I miss Morrowind in Bethesda's concept of making a game. Allowing you to go anywhere, anytime without issue or join every single guild is definitely not making their games better.

Lastly... did you seriously used BG as example for levels being meaningless? The game where a rat could one shoot your mage on lvl 1, but by level 3 they can already pretty much get apocalyptic, not to mention going totally overkill at level 5. And then there comes cloudkill.
Yeah, levels mean an immense deal in Baldur's Gate.