I barely have time to cube and go to prereleases these days, but I think Goblins are probably competitive again. A few things took Goblins out of the picture:
- Critters started showing up in brown lists and blocking goblins
- 4x Mentor meant that a single Jester's Cap effect wasn't lethal
- Eldrazi got printed and are actually much harder to kill than artifact critters
- Abrade Goblin is maindeckable as a 4x and kills all the colorless and brown problems that can ruin your day
- Mentor got restricted, greatly increasing the value of cap effects vs Xerox engines
- Legion Warboss is everything Rabblemaster needed to be: go-wide, pumps Lackey, makes hasty tokens to hit planeswalkers. Unlike Rabblemaster, it doesn't force your other gobs to make bad attacks.
- Trashmaster lets you trade up vs brown
- Warboss + Trashmaster let you go back to being an aggro-combo deck vs Xerox and aggro-control vs brown. Earwig Squad "combo" isn't a sufficient angle of attack vs Xerox anymore and you had too slow a clock without it.
- Assassin's Trophy lets you switch from Grixis to Jund and adds redundant disruption against everything but fast combo (where Earwig Squad seemingly still does all the work you need). It's cute that it gives a maindeck answer to Oath, too.
Anyways, I think these recent printings probably bring Gobs back. I'm happy to help people brew if they're interested.