I can see what you mean about carrying a party that wouldn't clear without such an experienced healer but personally even in those situations other cards seem preferable to Spear to me. An enhanced arrow on myself is like getting a mini lightspeed in, if an inexperienced tank is pulling big in a party with no AoE I would get in Noct stance, shield him and use Balance on myself to gravity spam the mobs down if my DPS are poor. Bole becomes more useful in that situation as well whether it is on the tank who is holding aggro but taking tons of damage or on myself/another party member who is "tanking" because that inexperienced tank can't hold their threat.

Basically the cards still have more use in the situation you describe when they are something other than Spear. They are flexible and hold real benefit even when used in non-traditional ways. The use of Spear is really hard to justify when it is taking the place of some of these other effects though I do agrre in a carry type situation Spear could potentially be more useful as it's original effect than as a Lady/Lord.

So yes, in this specific scenario I can see at least not Minor Arcana'ing a Spear.... But only as a last resort and even then only if I am going to be able to trigger several oGCD abilities.

It doesn't make the Spear good really, more a very underperforming party makes the alternatives worse which makes the huge disparity between the effectiveness of Spear and Balance/Arrow seem smaller.

Also I find it hard to swallow that you consistently find yourself in these vastly underskilled parties unless you are somehow searching them out in which case your play experience differs so much from the vast majority of AST's (and indeed players in general) that the relavence if your experience degenerates considerably. It's like a Dark Souls player giving Skyrim advice - yeah, they're both open world RPG's but the similarities end there.