I'll be honest in saying that I'd rather see new IPs, or the continuation of existing ones (set in the future or whatever) than I would reboots. In my opinion reboots pretty much shouldn't exist at all, if you want to use an existing IP, build on it, don't re-start it. If you fear not enough people are familiar with it for it to stand without a re-introduction, then it's probably a bad idea to use it to begin with.
I'll also say that they should probably leave "Terminator" alone. The reason is simply that it succeeded by being low-IQ fodder. Basically it was a very easy concept to get one's head around, an indestructable robot, with the time travel aspects being present mostly to hint at something deeper without becoming the focus. I think "Sarah Connor" failed largely because it decided to expand on the time travel aspects, much as you would expect, and it wound up going over the head of the everyman that doesn't want to worry about who might be doing what and when. That's nerd-fodder, and not something you typically expect the mainstream to embrace, especially when you focus on it to the extent of a TV series. Time Travel has to be kept very simple for the lowest human demographic. I'd personally love to see another attempt, but right now I don't think humanity is up to the task, as horrible as that sounds.
As far as "Howard The Duck" goes, I suppose it's possible, given that one of his big schticks is to parody existing super heroes within their own universe, and incidently is arguably one of the most powerful heroes ever because of it, I could see him showing up, but only when things have gotten more established. Right now I think the Marvel movie continuity is a bit too fragile to really have an audience getting into Howard showing up with his "Iron Duck Armor"
or using "Quack Fu" to fight as well as Captain America. That is kind of the point of the character, and it's also why a stand alone movie with him by definition was going to fail from the outset, because he by definition needs other, long established heroes, to exist alongside and satirize and parody to really work.