Rasputin Dreamweaver does provide a lot of value, and even the limit of seven dream counters still allows you to do some busted things
Thats trivial if you surround it with cards that roll d12 or d20, and you can use its abilities to roll dice, further feeding the synergies
Thrun, the Last Troll This is an uncounterable creature that also cant be targeted but can be regenerated
Late-game card draw when they run out of gas
Similarly, it won't be subject to the turn-based action that adds a lore counter to each Saga you control at the beginning of your first main phase each turn. Suppose I have Summon: Bahamut in play, and place a second lore counter on it
In the early game, you wont have the creatures to sacrifice or the mana to spend on the card you exile