I totally agree with this. It's a real pity to miss some of the content because of the high lvl. Manual entry would be awesome and Epic Skirmishes would be great as well - for some people who have less time for playing.
Yeah. Oppresive Force sucks.. but for me AS is a must - definitely for dungeons; even your group members usually love it :D. Ice Storm has awesome effect, it's fun but in the dungeon it just makes a mess.
The main advantage of CoI in the mastery slot is that it adds chills (5x over the whole length of the spell) which slows the mobs and gives you better chance of kiting them (if you use your teleport right). About the Chillstrike, I might do that when I hit 60 .. but there's no need for it now.
It doesn't feel that way to me. Since I put conduit of ice into a mastery slot I haven't had a problem.. and once you gain singularity, well, you can even take on multiple groups at a time and never get under half of your HP.