Destroying items with AoE spells might only be a solution when the destruction of an unmovable object would offer an alternative path, i. e. the only path the character can take (this is only the case when characters block the path to a character's actual target or the path to items that block the path). Destruction of movable objects would not achieve what moving items couldn't achieve, though be a bit more effective in some situations - but I would not know when to prioritize this (and I can't check which items are destructible). As you say: it would be the last hope for a desperate man, but solving anything otherwise unsolvable with this is very unlikely.
The main source of desperate/unsolvable situations are the path blocking characters (though there's always at least one NPC who's able to act, if you don't control him with status effects). I'm currently thinking about strategies here, but they would produce more flaws than benefits; characters don't know if their path is blocked by items or characters (or both) and can't know if an NPC standing around is actually blocking their path or just there for sightseeing (not relevant). They'd have to guess, and not only trying to move items but also asking and causing nearby characters to step aside, often for no reason (and where shall they step to without risking to block another character's path or block a path to blocking items).
I suppose this is a field of impossible improvements.
I would really like to offer quick and elegant solutions for every situation, but some situations will remain complicated - though a permanent all-characters-skip-turn situation should never happen in any case any more.
