Everything found so far is consistent with a high-speed impact. The flaps were probably up when they detached, and you're not likely to find pieces of seats floating away if the aircraft was mostly intact.
BTW, apparently the Malaysian government are talking to a company who have offered to conduct a search for free so long as they're paid if they find the aircraft. So we might finally get some answers soon.
New hope for families of missing MH370 passengers | News24