Maybe I am misunderstanding you...but in nearly all the FF's party members could summon summons. Rydia, Yuna, in FF7 and 8 the whole PT, in FF12 you could summon it and become to summon. In FF6 you could summon stuff on any character also. The summons weren't that hard to obtain ^^; In FF12 though they were...haha the fights were a pain but a lot of fun!
I don't like the whole "one shot" anything either, that is kind of silly and takes the fun out of bosses and stuff. Is it really worth it to use in PVP too? It would be funny I guess lol but nothing that epic.
FFXI I think they did a good job, at first anyway. They really used to make you work for the avatars...there was only a very small amount of us summoners in 2003 - 2005. I wrote a guide on it back in the day at gamefaqs

But then when they made it easier and everyone and their mom leveled it for the wyrms...yeah that is when it felt like it lost its novelty.
I really hope he does add summoner job...I know a lot of people are expecting it and if it does not come out I also will leave...I been waiting for it ._.