Your problem is getting through hexproof and indestructable? Well, you have two options. Either Gatekeeper of Malakir or Black Sun's Zenith. They're not perfect, since they'll kill most of your rats, but it's an option.

I don't play rack, but I do know that for pack rats, Liliana of the Dark Realms is, in my opinion, a must-have so you can fetch a swamp, then discard it to create a rat token.

For indestructible removal + mana, try Gild or King Macar, the Gold-Cursed. As for actual rat cards I would suggest adding in 1 or 2 Marrow-Gnawers for lots of rats to pump Pack Rat.

What most 8 Rack decks run is 4 copies of Smallpox, which gets around hexproof/indestructible. You might lose a creature in the process, but better to get rid of some indestructible thing AND a land AND a card in hand then lose a game to something you can't remove. You don't have to run 4 copies, but I strongly recommend at least 2. Also, if you can get them, Thoughtseize is better than Duress, and I run a combination of Raven's Crime and Dakmor Salvage, so that if you can get your oppoenents down to one or no cards, you dont have to worry about drawing if your board state is good, just keep recycling the Dakmor Salvage.

Alphamew17, your points are valid. My only issue is that my deck runs on few lands, yes but these lands are extremely important! I run an aggressive 21 lands and three of these are utility, so I need every land I can get up to turn 4-5. This deck as you know excels at getting edges, yet I view Smallpox as setting you back as well.

Ah yes, the problems with running creatures. What about Liliana of the Veil? Her -2 makes opponents sacrifice a creature, and the +1 is also beneficial. Also, I like the Nezumi Shortfang, currently I'm running some other 2 drop that isn't Dark Confidant, and that would actually be a pretty good replacement for it. I'd have to mess around, but having an extra rack in creature form could be nice.