Yeah I forgot about PvE indeed, most because its not challenging. If we indeed had a good PvE and we could also have quests for certain levels. You are right to say that because this would be a unique situation since that in single rts we could load and do again when we fail, but in online mode we are not alowed.
Taking this in consideration indeed paying to revive your troops could be a solution. Or even paying to level more than level 5.