Radical Idea Jump-start can be an effective ability in the right circumstances, but you have much better draw power available for two mana
The Un -set was perceived as a smash hit but was overprinted and ultimately netted a negative profit
Conversely, trimming a Cube is a matter of eliminating archetypes and redundancies at the higher points of the mana curve, thereby tightening the power band
Adding more value to him is the fact that late in the game you can transform him and either dig for more resources, blow up any creature/planeswalker or recur something from any graveyard
Not only is he rocking the butt off of those fancy jeans, hes also looking seductively back at the viewer like hes in a commercial
Anything that produces 1-2 Energy is providing a fraction of a cards value, so it can go an a card thats slightly underpowered for its mana cost