We do not know where the har habayis borders are... Whatever you see today means nothing.
Todays mikvah doesnt fix the issue why we are not allowed to enter that area.
If someone wants to go close to the har habayis to pray & risk one of the more stringent rules in the torah then so be it but it comes with a very heavy price.
Hashem accepts tefilos wherever you are. not one tefila gos unheard