I think it's great that you're toying with Underworld Dreams. I'm not sure how effective it is in this particular deck, however.
-oath into griselbrand- he now reads pay 14 draw 7 which is huge in itself not allowing them to draw 14 and leaving them at most 6 life to play with not taking into account vamp-ts-orchard token hits-fetches-an army of goblins-plus the dreams itself.
jace tms- bolt to the face. if they use the bs ability on 3 counters he can kill himself. either way makes digging w jace slow way down and become painful quick.
standstill- if you get turn 1 ritual dreams and they dont have fow or mm you probably won whether u get another bomb or draw 7 off or not.
bomberman - puts a big halt on drawing your deck w those spellbombs.
wish.dec -between my draw 7s and theirs dreams can def cause problems for them.
The problem with most of these situations is that Underworld Dreams is marginally effective after your opponent has developed their hand/board state. You DON'T want to punish oath after they've gotten their Grisel in play. You're probably better of if they never get it into play in the first place. Same with Jace. Your chances of winning are likely better if Jace never enters the battlefield, Dreams or no. Landstill- yea. it's probably a house versus that deck but getting it in play versus all their counters isn't easy. If they've run out of counters, well, maybe you should just Belch them out instead. If bomberman is in a position to draw a bunch of cards with spellbombs then they've already siezed control of the game. Giving a Wish deck draw 7s is less than ideal.
Belcher has always been the deck that wants to end the game as fast as possible. Underworld Dreams wins over several turns by nature. I haven't played your list but this seems like a conflict of interest.
Dreams doesn't help you versus the Workshop matchup and that is going to be one of your hardest.
It's been a while since I've played a Charbelcher list but my favorite cards in that deck were always Goblin Welder, Land Grant, and Xantid Swarm.
Good luck.