Not arguing that PUP has it bad, merely responding to the "PUP gets it easy" comments. I don't really think it's hard at all to use my automaton and level it up. I leveled magic and melee while soloing with the white mage frame, and leveled ranged with a few days out in ceizak using the alternator when it came out. My point was the "PUP can get level ups while just auto-attacking!" Seemed kind of like a "this job gets X, why can't I!?"
We also have three times the skill levels, four if you include our own h2h, to level up compared to you. One skill that you can easily summon Carbuncle for and spam poison nails (if you're worried about mp) and healing ruby, or you can just summon, unsummon, summon, unsummon. I would recommend the BP path though, hitting things of a level higher than the equivalent level that your skill is at tends to get you better skillup rates. Walk of Echoes was the best place to do it, imo; I only have the eminent satchet rather than a seraphicaller (no luck on winning a lot yet) and my Garuda can tank 2~3 harpies (though 3 tends to shorten her life span significantly) and a Pclaws can do anywhere from 7~10k damage. Of course, if skill is low... then you might as well use one of the magic BPs. Even if the damage is low, at least it'll hit and give you a high chance of skilling up.
Again though... manuals. Sparks are not hard to farm, and summoners have it fairly easy to cap skills. Farm sparks using BPs (PClaws and Chaotic Strike tend to do well for 500+ damage, which is 5k Limit Points and 1k sparks per completion) to skill up, and then use the sparks to buy manuals and go further.
And finally... how does an avatar hitting a monster have anything to do with your summoning skill? With an automaton, you're getting better at aiming your puppet's physical or ranged attacks, or more practiced at using their magic. With your avatar... you're not summoning anything when it auto-attacks. You get skillups when you SUMMON for SUMMONING magic, or when you use their Blood Pacts, which is summoning magic that unlocks a special ability of the avatar you have out for that brief attack.
Sorry if this is turning into a "pfft, I hate your idea and it sucks!" I just feel that quality of life is turning into a laziness deal, especially when it's not hard to skill Summoning Magic between manuals and soloing, or even group play if you have friends who will take it along. I personally don't get to take my SMN to anything, but leveling it solo and doing a few solo things (mostly WoE lately though) isn't too bad.