You bet I did. Being a methodical player I am and with little free time to re-play games (I have a huge backlog of them and......achievements/trophies, LOL), I always do some "research" and plan ahead before starting an RPG so I won't later regret doing something stupid in the beginning, like killing a quest NPC for example. And uesp.net is really informative when it comes to quests and gameplay bugs.
Did you use that to help you plan? This helped me a lot. I went from like 100 hours in my first playthrough to 75 hours in my last playthrough. It helped so much because I made sure I didn't mess anything up.
I hate how when you're like level 5 or 6 it takes like 10 hits to take down a bear. But at level 45 it takes like 100 or so.
As for level scaling, I agree that it is somewhat unfair and annoying to punish players for trying to max out their stats, or gaming experience, so to speak. But there are some perks when you max out every stat. But yeah, the scaling is ridiculously out of proportion.
I've got the PS3 version as well, but separately with Oblivion (which includes KotN) and SI. There're no other add-ons whatsoever on the PS3. Also in the GOTY version, there is a serious vampirism bug which Bethesda did not bother to address. So guess I'm getting Skyrim for PC.
I'm not sure. I had a PS3, and there wasn't any DLC.
Just The Shivering Isles and the Knights Of The Nine I got with the GOTY edition. There was a good amount for the Xbox though.