At my table, Warlocks should expect their patron to be relevant. When the campaign starts, the patron may be unaware or mostly uninterested, but that will change as the warlockās power grows.
I donāt really see the point of the warlock if the patron is not mentioned. Itās a roleplaying game, and thatās the warlockās core roleplaying hook.
Well, let me give perhaps a slightly different spin here.
Does the Fighter have to worry about whoever paid for them to go to Fighter school coming along and demanding back all the money they paid?
Does the Druid get an avatar of Nature herself showing up one morning demanding service, or else she'll take away all the Druid's magic?
Does the Wizard have to sweat about the possibility that everything they've studied and worked for could just disappear, not just their notes, but literally magic itself just abandoning them, without explanation?
I understand why you want roleplay hooks. I think it's good to have them, and I think players should be open to this. That said, I also think that it's reasonable for the Warlock to ask, "Why should I be subject to worries that I'll get to keep playing my character, that nobody else has to deal with?" It's not like the Warlock is stronger than anyone else. (Arguably, it's
weaker in many ways; that's why 5.5e buffed it.) Yes, it's cool to leverage the story of transactional power to create richer, more interesting experiences. That needs to happen in a way that doesn't make Warlock players feel singled out for special harsh treatment.
Your intent--like the others in this thread--is almost surely not harmful. Or, at the very least, you want any such "harmful" things to be only harm perceived by the character, not harm felt by the player. But if we're going to be asking, "Why would players be so strongly against this?" we need to consider the player's perspective, and that perspective is likely to be one of wondering why they're getting singled out for special attention when the Warlock
as a class doesn't offer much that is terribly impressive or extreme compared to any other class.