I agree that some of these abilities might need some work to be on line with others... but I personally think Summoner, Warlord and Beastlord are just as useful as the 3 you mentioned depending on your playstyle.
edit: diplomat is also really, REALLY good
Summoner would be useful if there were more creatures in the game that could be summoned and if the chance of getting the summoner traits would be higher for a summoner.
Warlord would be useful with a 75 % reduction and if the wealthy trait would not do basically the same.
Beastlord would be useful if the spell had a range and a lower casting time.
Diplomat is nice, but it is not as useful as the combat professions, because the combat gives you xp and loot.