This. Krylian is just using age-driven logic which doesn't even apply to pitchers as much as it does with hitters. Merryweather has MLB-quality stuff and he's already knocking on the door, thus he is obviously more valuable than a comp pick. The small likelihood of finding a superstar prospect with a 2nd round comp pick is there, but at that point you also have to consider that there is also a small chance that Merryweather finds one small improvement and ascends to a higher level himself which is entirely possible with any pitcher who throws mid-90's and flashes above-average secondary pitches while showing the ability to throw strikes.
Look at someone like Kloffenstein (who we should rightfully be hopeful about) who we got in the 3rd but paid 1st round money to. He was 90-93 in his limited outings in the GCL while flashing "potential" secondary pitches. Yes he is just 18, but it isn't even a given that Kloffenstein even becomes Merryweather. Merryweather certainly already throws harder, and while Kloffenstein could grow, it isn't abnormal at all for HS pitchers to hit peak velocity at 18/19. He could also jump into the high 90's and become a superstar, or flame out in A-ball like a ton of other HS pitchers do.
If you look at it objectively instead of focusing on "hype", then Merryweather is obviously above a 2nd-round comp pick. There is also a reason why Cleveland put him onto the 40-man roster after posting a 5-whatever ERA as a 25 year old last year: there is obviously something there, and if you read actual scouting reports its pretty easy to see what it is.