I know some folks like the feel of knockback, especially when soloing. Watching everything get knocked on it's butts... But in groups, especially when AoE pools are placed on the ground, watching attacks knock everything back and out of those AoE zones (thereby voiding their beneficial effects) can be rather annoying for the folks placing them down (or for tanks that heard a group into one spot). I always recommend adding in Knockback to Knockdown IO's into powers prone to have lots of Knockback, if you plan to group a lot... Of course, play how you want to, but I like to throw that caveat out there, because it is annoying to watch all your powers get nullified by other players powers knocking everything out of your AoE's, especially for classes where those are your more useful abilities for debuffing and crowd control (such as the various rains and hold pools)...
And I whole heartedly agree with changing out Power Blast with Power Bolt. Sure Power Blast does more damage, but Power Bolt has a faster cast time, comes back faster, and is a great mule for Decimation: Chance for Build Up and other procs, that will help make up for its slightly lower damage output. The first two powers in most attack sets, tend to become fillers mostly in the late game anyhow, depending on your build. Acting more as Proc mules or Set Bonus hosts, then anything else. Also, Sentinel's Ward works better in shorter cooldown AoE powers, so it has more chances to proc. You can still use it in your most used power as well, but if the power containing that set is used more as an occasional filler, then it's Proc benefit becomes sorta nullified.
I also think that at end-game, you have way too many attacks in this build. Unless your just using them as Set IO Bonus Mules, you'll find that your more powerful attacks will come back fast enough that some powers will rarely need to be used, and might feel like wasted power choices as you do various end-game group activities.
Also, focusing on a ton of various higher resistances while at the same time avoiding most defenses will feel a bit counter productive. Just because you take less damage when hit, the fact that your getting hit all the time because of low defenses, will just end up getting you killed regardless of taking less damage per hit. High Health Regen will not compensate for it either, as the health return doesn't come back fast enough if the damage is coming in too fast... More so if you plan to stick with knockback, because if you knock stuff away from members taunt auras or out of control fields, with high damaging attacks, you will end up drawing the agro from some, if not many, of those baddies effected, which means more incoming attacks towards you... And so on...
When it comes to Sentinels, I find that if you plan to choose a Resistance Secondary set, then you need to work towards capping only the few most common damage types (such as L/S and a few others), and when selecting IO set bonuses, you also need to account for shoring up your lower defenses. Same goes for Defense Secondary sets, using IO bonuses to shore up common resistances once the more common defenses are shored up. It's a balancing act, to either try and avoid getting hit at all, but if you do get hit, the damage will be reduced. Or going with some moderate defenses so you get hit now and then, but take less damage for certain damage types... Problem is, if your getting hit all the time (compared to now and then), no manner of resistance or health regen will keep you alive for long, and this build has really low defenses across the board, other then Melee, which you should only have to worry about when you run in to Nova.
Now all that being said, you can compensate for some of those defense holes, by selecting the right Incarnate abilities as well.. So take that into consideration before scrapping this whole build based off my comments, and trying to rebalance it all... 🙂
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