Not at all.
You are talking about introducing yet another additive output modifier to the large number that already exists.
The economic base in Stellaris is based on POPS x (1+SUM_OUTPUT MODIFIERS)*, so introducing a new 25% modifier for specialist jobs would not provide anywhere near 25% extra specialist production.
Take my most recent game. By 2305, on my best research planet best researcher produces 14.1 of every resource due to having a total of 253.2%** output modifiers from various sources (and 4*3.532 ~14.1). It would be higher if he was intelligent. Giving +25% specialist output would thus be equivalent in this case to having (1+253.2%+25%)/(1+253.2%)-1 = 7.1% more POPs researching.
Even unity, where a lot fewer modifiers apply, the best located ruler POPS have a 113 % unity output modifiers from various sources, and for them 25% extra would be equivalent to (1+113%+25%)/(1+113%)-1 = 11.7% more POPs.
So unless the significantly increased base growth we've seen in the diary is somehow not enough to provide more than a roughly 10% POP advantage, you'd want a much higher bonus if you wanted total production to be competitive between low POP growth psionics and high POP growth genetics/synthetics.
But on the other hand, early in the game at the earliest point you can get Psionics at 3 perks and not all that many POPs (yet), players have much lower output modifiers and adding 25% or 50% or whatever value was thought to be a good mid- and end-game value would completely unbalance the game at that point.
Which leads to the obvious question, "so, Peter you smartass, how about doing this as a modifier to the POPs base production, just like Mining Guilds, Merchant Guild, Exalted Priesthood etc? Say that they get +1 to everything, or perhaps that each POP counts as 1.2 POPs?"
Then you get the problem that as planets get closer to being maxed out for jobs (and once they are), psionic POP planets will be much more productive than anybody elses planets are, for a very unbalanced late game. (Unless you add something small enough that this isn't a real problem in the late game, in which case it is unlikely to be large enough to help balance in the early- or mid-game when planets aren't filling up).
Ever since 2.0 POP growth has been king, insofar as any single factor can be said to be so in Stellaris, and it is a very difficult system to tinker with for economic balance unless the radically different empire forms nevertheless end up with roughly the same POP growth rates so can be expected to have roughly the same amount of POPs with roughly the same amount of effort.
I am not saying it can't be done, but purely from a mathematical point of view the chosen POP/job model makes it difficult to find a solution that is both neither too powerful nor too weak in the early game and neither too powerful nor too weak in the late game, when it is compared to the empires that have higher growth.
---
* and for research POPS x (1+SUM_OUTPUT MODIFIERS) x (1+SUM_SPEED_MODIFIERS)
** sounds high? relic world, tech world designation, highlevel intellectual governor, highlevel research assistance, 3x+20% techs, traits, stability, research institute, event modifiers, and finally all the slave modifiers as my best researchers are all indentured servants (both worker and slave modifiers affect slaves regardless of stratum of job, so between the slave building, workplace motivators tradition, and extended shifts edict, and authoritarian that's another 40%, 45% if fanatic). It all adds up.