I think you have combined two things and it clouds what you really want. If you can get that much for the same price, even if only for two years, go for it and forget the EHD.
Staying with a carrier should be because they give you as close as possible to what you want, more than others. If that's no longer the case with Dish, time to move on.
Taking money out of it, if you want to stay with Dish and like the hopper, and the programming better than what Direct TV offers, then that should be your choice. If not, again, go with Direct TV. If you stay with Dish you will be able to play at least some programs, possibly not all. You will have no access if you switch.
I would say at this point that material is not going to play for some people, it has been posted others can play past freeview material.
Your question is a good one, the unfortunate part is the it was answered by DIRT as, no, there is some material that is not meant to play if you do not subscribe.
The problem is, and what still clouds this issue, the information given to DIRT was very wrong when they answered. They were told this applies to other receivers as well, but that is just wrong. In all the years of having a DVR with Dish (since they started even offering them) never have I not been able to play any material recorded subscribed now or not right up to this minute. So to me, Dish is only doing this with the Hopper, or it only happens with the Hopper.
Also clouding the issue, there have been posts from people who can play freeview material or from channels they used to subscribe to.
Since the only official answer I have seen did come from DIRT, I have to say you should go on you will not be able to play all material.