I'm over here sinning with T1 Entomb Sire of Insanity, T2 Animate Dead so I'm gonna have to pass on the "what is a fair return on 2 cards and 3 mana" question, because my perspective is way different than most here prolly since I like a little busted-ness here and there and I am a firm doubter of Tinker's appropriateness for non-powermax lists
Most of the time, you'll cascade into another permanent thanks to the decklist's low non-permanent spell count
Shrieking Drake, Ornithopter, and Intruder Alarm generate infinite casts/enters triggers for cards like Beast Whisperer and Sage's Row Denizen, as well as infinite creature-only mana
with enough creatures you should be able to get one or two through for a huge sweep of damage
Add in a few flicker effects to reuse your best ETB triggers once you get going, and your opponents wont know what hit them until its too late
Does Cycling Count Towards Storm Count