well theres no way a boss will give out gold.
but more bosses overall would be nice, these 3 gems have been in the game for a long ass time, and i remember when they were first released most ppl were having trouble with the 2nd gem (lol the 1 below demon, whatever its called). now id say there are plenty of ppl capable of soloing demon gems, obviously time for a change.
as for holiday specific gems, there are always 1s for well known holidays. but if u asked PM, he would say its too much work to create a gem for other holidays and it would only keep them from working on the next expansion.