After a soldier died, it is still possible to recover the armour unline the bonus ones.
At least in Legendary Difficulty where resources need to be well managed, it should be destroyed when a soldier dies to hurt more the player when get a loss.
It is not about fun but about difficulty. If you play without bonus armour the game becomes a real challenge to get resources to equip your team, and if it were destroyed when a soldier dies the game becomes even more challenging.
I loved legendary xcom and legendary Phoenix point. All games are for fun, some things add amazing challenge. This would not, it would just make it nit picky and tedious. That’s my feeling anyhow.
And I think that all items on all difficulties should be damaged or destroyed in combat. And when only damaged then should be repaired only when taken to base (so repair not only to Cybernetics in any place or only aircraft repair when in base with functional vehicle bay).