Depends on when you are going. I think this 2 hour only deal had to do with a few things. One, FJ is having constant breakdowns and isn't ready to cycle with people for more than an hour or so at a time, so they limit the times available to ride to lower expectations of guests. Two, this is Memorial Day weekend, where they expect to be overrun with locals by noon, so best to have WWoHP closed off before they get there to lower their expectations of being allowed in. Three, lots of crazies on various boards (mostly AP holders and locals) who feel entitled for whatever reason, have been threatening to storm the gates and demand entry this weekend. For security purposes, its better to have the gate closed before the mobs decend.
I suspect by Tuesday, they'll be ready to let more guests in for longer periods of time.
But regardless, at least you know about the possiblity ahead of time and can plan accordingly. You'll have contigencies in mind and can go with the flow, make lemons into lemonade, etc... no matter what they do while you are there.
And if you are going June 19th or later, no problem, because by June 19th WWoHP will be open from open till close of the park.