err.. you got a little mistake about
Reassembling Skeleton: the activated ability brings it back to the battlefield for 2 mana, not to the hand. so the skeleton is cheaper to play, but
squee is harder to get rid off.
I've thought about your deck ant the Problems you run in. Then I reallized that you might have the same Problem that i've encountered severval times: Missing Focus.
Step back for a moment and think about what do you want to do with the deck. after you are sure about what do you want, think again about the cards you have added.
like you already wrote, you started with mogis/kaervek with a punishing deck. this usually uses alot of enchantments and a pillowfort. bunker yourself in and let them bleed dry.
Thats kinda different to Ruric Thar. with him you usually try to get alot of creatures, and try to punish every deck that isnt focussed on creatures as well.
Then
Shattergang Brothers are different again. With them you usually play alot of shitty stuff, sacrifice it and get it back again while your opponents lose all their precious goodstuff. Then kill them with your truckloads of shitty stuff, or use some cards like
Beacon of Unrest to use their goodstuff against them.