Well his 'sand-shield' which reacted automatically was from the Shukaku (hope I hit the right name for the one'tail bijuu
The control of sand in general though was his own jutsu (like Shikamaru's shadow'imitation jutsu)
Well about is he lost or gained power it was somewhere else a discussion - I think in the "Gaara vs. Kisame"-thread - and it is difficult to say something since nothing was said about it.
If it would be like with Naruto, where several times was said that without the Kyuubi he may have far more chakra - I think cause alot of his chakra is used to keep the kyuubi imprisoned (my own opinion) - this would mean Gaara would be have more Chakra now too and would be in total seen stronger.
He could use still a sand'shield but would need to fully controll it himself now, so maybe the 'learning' of not thinking it's automatically will weaken him for a time but afterwards he would be stronger.
However: Nothing was said if it is for all with a bijuu inside them the same, so actually it 'could' have weakened Gaara... difficult discussion since some think it is like with Naruto other think it weakened him alot.
I myself think it is like with Naruto so he will be stronger after he learned a bit to not have an automatically defense.
The goard he has not anymore, yes, but he still can control sand in general...
So well in general 'my' opinion is: he will be stronger than before, so same like with Naruto (at least which was said about him and the Kyuubi).
About the eyes... well would make sense that it fades away, though I don't think too fast since he was used to not be able to sleep for several years (since he was a child or even baby) due of the nightmares... so I do not expect him to be able to sleep now directly all okay.
And well... these eyes are Gaara, so actually I do 'hope' they not disappear, would make him look a bit strange if you ask me.
So far from my opinion *smiles*