Arrestor hook landings have already been looked at for the Typhoon, afaik it didnt go well, im guessing the structure isnt just upto it. Plus I dont think they would deal well with the salt and corrosion issues associated with carrier use, a lot of areas of the Harrier have been designed with this in mind from the start. They probably have enough thrust to get off the desk with a ramp but recovering could be an issue!
There is a rumour going around that Harrier and JSF will be scrapped, and that Super Tucanos will be purchased to replace them... :cry: