Without other supporting cards like Foolish Burial or Diffusion Wave-Motion, it is simply too slow for today's metagame
That was a good time when Timmy met Spike for a powerful haste-enabling Smash Machine
In rogue decks this creature is usually a 5/3 menace or stronger for only 3 mana, and decks that want as many rogues as they can get, like Anowon, the Ruin Thief EDH decks, love playing these cards
Assassin specs should light up from time to time, especially because these are all Modern legal
More than 15 Trainer cards and 2 new Special Energy cards
The latter is mostly due to the lifegain, sure, but getting to bring creatures back even temporarily can be really strong