"Actually, Poly Other specifically states that a creature can be polyed into "itself", which still exists apparently somewhere under the magic effect."
The effect you are quoting, which I assume is the newest version of Polymorph Other in the Tome and Blood, is in the significant physical qualities (such as height, weight, and gender) paragraph. I agree that you can make the appearance of the creature be whatever you want.
However, in paragraph five:
"The creature's new scores and faculties are average ones for the race or species into which it has been transformed."
No mention of it giving back your same physical stats.
"I suppose this avoids a dispel check, but forces a save. "
You can always voluntarily fail a save.
"However, sometimes the average stats are a good thing. For example, in a point buy with a low number of points, a wizard take very poor physical stats to boost INT, and then polymorph into an average person to boost them."
Yes, you could do this, however, your previous Con determines your hit points and the ability score increases you receive for your character level cannot necessarily increase these average scores.
(That is a different debate entirely.)
Besides, if you have less than 10 in every physical stat, then gaining 10s in your physical stats aren't really going to help your caster much.
BTW, this isn't really an argument against casting Polymorph Other on yourself.
You could get the same effect with Polymorph Self and suffer no disorientation and you aren't stuck in the new form.