The original intention certainly was to make it a tool for GA pilots
I couldn't agree more.
Somebody in the system seems to have dropped the ball.
There is however a remaining issue with AFPEX which affects
IFR pilots: you need to have internet connectivity the whole time up to (nearly) departure, in case a slot gets issued for your flight plan. Normally the tower would get a copy of the slot message and they would advise you but you need to have the radio on all the time (be sitting in the plane) on the tower frequency. This is why many people will continue to use homebriefing.com because they send you SMS messages for slots etc.
And mobile internet access to AFPEX is a major problem because of the ~ 5MB java download which is enforced on every login. On GPRS, this makes the service nearly unusable (of the order of 30 mins download) and while it would work on 3G, if you are on PAYG the cost would be about £20-£50 just to log in. Only contract data users with monthly allowances (these are not usual when abroad, roaming) will get around this, though of course at a price paid indirectly. AFPEX should get rid of that completely pointless download.
I will use AFPEX for flight plans on which there is no possibility of a slot (VFR, or IFR wholly OCAS), and use Homebriefing for the rest.