Alakazam was only good in one gen, so definitely no. I mean, to put it into perspective, there is no way Alakazam deserves more than Exeggutor.I think 7-10 should definitely include dragonite, alakazam, maybe jolteon, and definitely suicune. CroCune = gen 3.
Jolteon was an bottom OU at best in every gen so not either.
BW is not being considered though (notice this is a RoA thread), so Jirachi is essentially a two-gen good, two gen non-existent Pokemon. Say, if I go back to the Exeggutor comparison again gen1/gen2 egg >= gen3/gen4 jirachi, and egg at least existed in the other two gens.Jirachi is extremely good (and OU) in ADV/DPP/BW. This seems like it deserves a spot on the top10.
I think the three remaining slots should be filled with Dragonite, Celebi and one of the two spikers, in no particular order. I don't think Blissey alone deserves to be above any of these.