I've just realized that if I run a G I can throw in some Descendents' Path and try to pull off some big creatures that way.

Would that be a good idea?

Yes, it is pretty slow and that's also one of it's problems.

I like the idea of running GW elves but my problem with that is that it may be overly reliant on Mirror Entity, as in if I don't get one within the first few turns the match may be decided for me. Of course, I'll still have the elves but for them to win a match alone might prove difficult.

To be honest, if the budget is that much of an issue I can quite easily get rid of the Progenitus and replace it with cheaper creatures.

I like the idea of bringing out massive creatures with Cryptic Gate, as they don't even need to be restricted to color!

However, if anyone has suggestions for the Changeling buff side of this deck that'd be great too! I don't think it's a good idea to keep both strategies in, or maybe it is. Thank you!

Well, this is my first deck I'd like some suggestions on how to improve it.

http://deckbox.org/sets/321064

Ok, few things to note:

I own none of these cards; my budget is $60 - 80, the lower the better!
Format doesn't concern me(Legacy, Vintage, Standard, Modern whatever) I play casually with a group of friends and have no intentions of playing competitively.

This began as a changeling buff to eventually "use changelings to bring out massive creatures".

The Didgeridoo helps me bring out changelings and by playing Cryptic Gate I can easily summon the massive monsters. The tutors help me get whatever I need.

I've also thrown in a few buffs for the changelings and the Kilnmouth Dragon has massive buffing potential.

It's currently all over the place, some feedback/help would be much appreciated, thanks!