Keep in mind that Morrowind had leveled scaling as well which I never heard a tiny peep of complaint about except end bosses not being strong enough.
Here's one from me: Around levels 5-7, critters in the West Gash became blighted. This added a lot of randomness to fighting (on low levels, one couldn't dream of having enough cure-blight potions at hand, let alone cure-blight spells, and fighting a blighted nixhound with endurance 60 minus 40 could be quite an adventure...), which most players probably solved for themselves by using Reload whenever they got the blight.
Oh, and daedra temples became a lot more dangerous with fire atronachs.
And there was some minor immersion problem when the Grazelands got swamped with Golden Saints. The NPCs there, however, remained stuck at their levels (including level 5 ashlanders). At that point I was really glad that NPC's didn't get into fights with creatures. However, in Skyrim this is probably going to be the case...
As for the bosses not being strong enough... Well, it has nothing to do with levelscaling. It has to do with the ability of the player to swallow 50 exclusive health potions at once, and with (most of) the people complaining about easy bosses having collected the best artefacts through all of the Morrowind. Some parts of gameplay indeed could have been balanced out better. This doesn't require levelscaling.
Thing is: If GStaff had said that Skyrim's levelscaling is like that in Morrowind, I'd be rather okay with that. But FO3 is a different story. I don't want to repeat what I wrote http://www.gamesas.com/index.php?/topic/1156332-is-level-scaling-backnoooooooooooo/page__view__findpost__p__16937933, but FO3 with Broken Still does suffer from the Oblivion syndrome: a level 30 character usually has a tougher life than a level 22 character. In vanilla FO3 this might be better, but I'm not sure (the level cap of 20 svcks, because it makes it too easy to mis-skill).
You want to know why leveling in Morrowind was relevant dispite the scaling? It is because that locations such as Daedric ruins and whatnot were not scaled down to your level, if they were then yes leveling would have been pointless.
I think you got something wrong about daedric ruins here ;=