Then by all means call them on it being rude, or unpopular (though you shouldn't refraid from giving your opinion just because you feel others won't agree with it) but don't say it's just nostalgia. I have no problem with someone criticizing my thoughts and opinions. The problem I have is with people assuming that I don't actually feel that way, it's just nostalgia clouding my judgment. It's very patronising. Also, I would be very cautious of claiming anything one way or another for a 'silent majority'.
Without derailing the thread too much ^^; I would say something along the lines of how Arcanist/Summoner/Scholar has been implemented. Where those jobs have three summon abilities that vary by which class/job you are on, BLU could have some Blue Magic abilities that vary by what you have absorbed.
Say for example you have the ability 'Lancet' (From FFX, I believe) and when you use it, your ability 'Blue Magic 1' will then correlate to an ability from the mob you are fighting. Use Lancet on another mob and it will fill your ability 'Blue Magic 2'. Once all your Blue Magic abilities are correlated with mob abilities, you would need to 'forget' an ability to free that slot up if you want to use a different spell.
Enemy abilities could have certain levels or tiers meaning they can only be set in one particular Blue Magic slot.
eg:
Blue Mage base class (Tamer maybe, or similar) ability list:
1: Whip Crack (yeah, my blue mages have whips). Single Target ability.
3: Lancet ( x% chance to absorb enemy ability for use with Blue Magic)
3: Blue Magic 1 (Can set Pollen, Bomb Toss, 100 Needles .... ). Combos with Whip Crack for enhanced potency
3: Amnesia 1(removes magic set Blue Magic 1)
5: Azure Affinity (Increases potency of next Blue Magic)
8: Eye Snap (Low damage ability with Blind)
10: Blue Magic 2 (Can set White Wind, Impish incantations, double Strike ....) Combos with Blue Magic 1
10: Amnesia 2
15: Azure Veil (Makes next Blue Magic AOE)
25: Blue Magic 3: (Can set 1000 Needles, Explosion, some kind of knock back move, Bad Breath)
25: Amnesia 3
etc etc, you could have traits to increase learning chance, stuff like that.
Nb the above is just something I came up with off the top of my head as an example, so don't criticise that it sucks because, well, I know.