He does have a variety of ways to keep him alive; unfortunately that doesn't earn him back the points you're spending on him. When you do the math, his attack sequence is almost completely evenly distributed between doing 2 wounds and doing 10. For 300 points you need a unit to be putting the beatdown on your enemy, not potentially doing a few wounds and calling it a day. The hand is fine, but I think it's being overestimated; in most situations you're probably only going to be smooshing 2 wound stormcast or cavalry, he's too slow to be hunting many specific targets. If you're up against horde armies (as is the tendency nowadays), the hand is pretty unhelpful.
I think giving him Ghyrstrike makes him something to be feared, but so is everything with Ghyrstrike. Without anything else though, he's unreliable at 300. Remember a Mangler is also 300, and just look at that thing's warscroll (and its synergy with other units!). I think his most damning feature is that other than his own command ability, there's no way to buff him. Everything in Gloomspite only affects grots or moonclan. Not saying he's terrible; just saying he should probably be a tad cheaper. People playing monster-focused armies usually have an uphill battle anyway.