Here goes. Yes having a respec would help to identify op items. However, respecs would also allow mercs to totally skip the standard and advance, not allowing them to be used creates bad data.

Reallocation would allow more players to spec into op weapons and out of normal or under powered weapons making them feel even more imbalanced. The UP weapons would be buffed and the op weapons nerfed, causing more calls foe respec and more rage.

Drop ships and HAVs were overpowered when compared to AV and were nerfed into a black hole because we all cried they were op and we got them nerfed. Now the AV is too powerful and HAVs and dropships are pretty much a joke.

Spending resources on providing repecs are detrimental to the team designing the game because they have even fewer work hours to work on the game and when people don't get one for whatever reason they get mad.

Respecs beget more respecs because they are expected to be provided because they did before and why not now or they make someone who missed it for whatever reason even more mad.

Some people don't read the forums or come her to complain so it would be an hour or so wasted reinvesting SP instead of playing. I don't get much game time because of work and the last thing I want to do is read for an hour just to play.

EvE is based on persistence and yes changing the stats of items is the opposite of persistence but if the gear is OP then it needs to be pulled back. No respecs also discourages specing into OP gear because they know it will be nerfed - sometimes heavily - and don't want to waste SP on an item that will be less powerful.

Lastly, people do dump SP into OP gear because it is OP and we shouldn't reward people that do if for the lolz and tears it creates. The people who do this are basically cheating within the rules. They know it and we know.