When you're high in roster power, but not too high, all your pvp matches- easy,medium, and hard, are essentially the same, in rune power and team composition.
Unless you have a massive store of Superior legendary 5* 4th trait runes, getting quests like- win 5 PVP with a dwarf, or win with 2 light heroes, are impossible.
Refreshing doesn't help, matchmaking still gives you impossible high rp teams.
not to say that's 100% accurate, I do very rarely get a 4000 rune power team I could usually handle easily, but with no yellow heroes capable of generating any offense, it's not use trying them against a 4k Shade/Zomm team.
ofc, skipping is an option, but then that kinda ruins the point of the game, doesn't it- just don't do any quests, danac, that solves all the problems!
You could fix this by changing matchmaking so easy teams are easy, but you can't change matchmaking, you s*ck hugely at that, it'll just make things worse.