The issue is basically that if you're someone who relies on henchmen instead of summons and you happen to crash (which happens a lot more often these days on Arelith), your henchmen vanish and you're left wherever you were but now alone.
Possible solution: When hiring a henchman, give the player a 1x1 item that represents the agreement (and have it vanish after a certain IG period - x hours similar to the lease of a ship or temp shop). If the player crashes or something happens, let those henchmen be recalled within the timeframe through the use of that item.
Henchmen also seem to be balanced around the idea that you can use spells to buff them up, unlike the summons which can't be treated this way. It means that if you're using some other means to keep them going (100% required in either case), you also lose the gold or spell slot investment. e.g. Potions, scrolls, buffs. Maybe instead they should be treated in the same line as summons, where they're adjusted to be at a specific tier and then potentially further aided by sequencers.
Also, henchmen won't -guard you, which makes their use extremely limited with the AI.