All concrete evidence leads to a new DMC:
First of all Capcom's new strategy about main titles getting a new release at a 2-2.5 year window. DMC4SE came out June '15 so they are right on track for a 2.5 year gap between the next entry:
Second, Itsuno's tweet about a new game announcement this year. He's the director since and not, Capcom's internal plans do not suggest another Dragon's Dogma series (which was never as successful as they wanted anyway). According to their pipeline, DMC is on the list of titles to be released at some point in the 2017 fiscal year (ending in 2018):
Dragon's Dogma ain't happening anywhere soon.
Monster Hunter PS4? I doubt how this is viable for Capcom on a global scale. It will sell strongly in Japan, everywhere else? Market is already oversaturated by those type of games. It wouldn't work.
Onimusha? Long dead and buried franchise that has become irrelevant. Cannot be considered as a major title.
About Ninja's Theory involvement. They are not developing the game in the first place. They might be back for a minor role as Capcom reverted back on it's outsourcing policy. Everything now is developed internally with a more tight budget:
http://www.capcom.co.jp/ir/english/data/oar/2014/growth/
There is no solid reason to expect anything other than DMC5 at this point.