I think WAAS currently provides Cat I whereas LAAS will give Cat III.
I of course accept ILS will be kept for those runways that can justify the cost but it's sad the authorities throw away the >99.9% benefits of GPS just because of the <0.1% chance of non performance. Approved units report loss of necessary accuracy if it occurs and have means of ensuring co-ordinates are correctly stored.
Incidentally I recall, many years ago on a crude version of Flight Simulator, an ILS display that was a series of moving squares that defined a virtual tube in the sky. The squares would keep coming past you, so you were trying to position yourself in the middle of each square as you 'flew' through it. If, for example, if you were too low the squares would pass 'above' you until you pulled your self back up into the glidepath whereupon you would be going down the middle of them again. It always struck me as rather better than crossed needles. The beauty of such a display is it could define curved approach paths as you could see the position of the glidepath ahead whereas needles only tell you were you are right now.