Mobility is a good example of where warriors can fail frequently at the highest tiers.
The Treantmonk playtesting was in the mid tier, and they specifically mentioned how much they appreciated the warrior having Cloud Jaunt because of its mobility.
That seems fair too. An onslaught of mooks should be something a mythic warrior should be able to manage.
When comparing spells, each 9 damage (2d8) that a single target spell deals, corresponds to 7 damage (2d6) that a multi target spell deals. Multi target deals less damage than single target, but it is still substantial.
Of course, we are talking about "typically", during official "standard" encounters. It is about frequency during gameplay.
When you say "bad at long distances" I assume you mean the casters gain frequent long rests.
The rest schedule is a separate issue.
Personally, I make every rest a short rest. However, twice per LEVEL, a player can change any particular rest into the effects of a long rest. This represents a "deep" rest, a return of hope, a new look on life, a rallying in morale. Because the deep rest only happens twice per level, the slot casters always have the same schedule as the at-will classes.