Yeah some classes will feel bad to level due to lack of skills but other than that there aren't really bad classes.
And then you have the usual mmo advice, tanks get instant queues, healers get fast queues, DPS get long queues. Long being 15-20mins generally speaking, but if you're leveling through the MSQ and have to take 20mins breaks(sometimes longer due to being older content, roulettes help but 30mins queues can happen for shitty trials and what not) it can be frustrating, so leveling a healer or tank can help alleviate that.
Tanks also have actually reasonable personal DPS for solo questing, much better than healers, but being a new tank might get people to yell at you and be annoying cunts and pull shit for you because they expect you to know the dungeons.
Finally worth noting, Summoner and Scholar are both part of the same base Arcanist class, so leveling one levels the other, which means you can for example play Scholar for group content for healer queue times and play summoner for solo content for higher DPS. Gear might be a problem however since they use different gear and you need ilvl to do group content, which means you'd have to pick healer gear from rewards, and then your DPS on summoner is going to not be very good, although it should be possible to get someone to buy you white vendor gear from the next expansion when you reach 51 and 61, which would help tremendously.