The dragonknight was the first class revealed back at the start of beta, and one of the first playable. The sorceror was the second. Anyone who followed the old 'official' ESO forums hosted on the bethesda site can confirm.
Templar and nightblade were both revealed much later into beta, and both received far less time for testing and feedback during beta. The dragonknight, sorceror, and templar all ended up having leaked information during beta, while information on the nightblade didnt come out until just prior to release (I think less than a month?).
Take one look at these forums and you can see that the vast majority of complaints claim that dragonknights and sorcerors are too good, and templars and nightblades (especially nightblades) have a lot of bugs, glitches, incorrect tooltips, and power balance issues.
Doesnt take a genius to come to the conclusion that the real issue here is the lack of attention, time, and effort the developers have given the last two classes compared to the first two. Given the timeframe that the classes were added back during beta testing, it's safe to say that we're technically still in beta for another 3-4 months (the only difference being that you no longer need a beta key, there's no longer an NDA, and now we're paying for the privilege of testing).
The biggest problem here arises from the fact that we've now got more resources and time being put into developing new content, and focus is being taken away from resolving leftover bugs from beta. I understand that different individuals are allocated to these two fields, but as a whole the developers are moving from finishing and polishing the game to putting out new things to keep players occupied (because, as we've already seen, those who rushed to v10 are calling out about being bored with the game already).
I really think that craglorn and additional content releases need to be put on the backburner until the base game is working as it should. The only way we're going to resolve issues with the classes, weapon skills, guilds, vampire/werewolf lines, etc. etc. is by putting them at the front of the line.
PS4 / NA
M'asad - Khajiit Nightblade - Healer
Pakhet - Khajiit Dragonknight - Tank
Raksha - Khajiit Sorcerer - Stamina DPS
Bastet - Khajiit Templar - Healer
Leonin - Khajiit Warden - Tank