They could probably just remake the first two at the very least. They've remade Medieval and the Tony Hawk Pro Skater 1+2 remakes did wonders for Activision (though it helps Vicarious Visions did the remake rather than farming it out to Robomodo like the not-so-good "Pro Skater HD" from 2012). Nostalgia for the fifth and sixth console generations of gaming is pretty big right now and remakes or remasters of games from that era are something many keep asking for.