Greetings from Georgia,
Speed is good, although as you already know, it is not neccessary to shoot 300 + fps. I started hunting with an old Whitetail bow and did fine. I later started shooting a 55# recurve with cedar arrows, no rest or sights and had a ball !! I see the speed trend in bows going at much the same speed as the trend of magnum cartridges in rifles. Just 30 years ago, a 30-30 was a good choice and a 30/06 was considered too much. Nowdays a 30/06 is considered marginal and a short mag or regular magnum gets a lot of press as being the best choice for deer. At the same time a station wagon or sedan use to be good for a family vehicle, but now we all "need" a great big ol' SUV to haul around the kids.
Keep in mind that for many centuries the Native Americans harvested game effectively and they never had wheels, cams, cables, stabilizers,oferdraws, carbon, aluminum, titanium etc., etc. I believe that once you have harvested game with a set up, you kinda get attatched to it. Get a new bow if you want one, but do not get caught up in the marketing ploy to convince you that all the speed and widgets are required to kill a deer.
Good Luck,
Dave