While I'm in the school of thought that Devin Harris is in a one-season slump (and not a TJ Ford slide into oblivion), I don't think he'd be a good fit with Tyreke.
The curse/blessing of Tyreke is that he needs to be the primary ballhander in order to maximize his effectiveness. Devin Harris is in that same category. I think it's best, in terms of our backcourt combo, to have two guards who can play off each other and both run the point and score. Beno and Tyreke seem to do this pretty well (although I'm sure we can upgrade) - Steve Blake and Brandon Roy are another example. But conversely, the Trailblazers have tried desperately to upgrade their strength at the point (Jerryd Bayless, Andre Miller) and those results haven't yet provided a noticeable upgrade.
If the team is looking to upgrade it's backcourt, it needs to look for a combo guard or 2-guard with point skills to compliment Tyreke and play off of him or lead the point when need be. If the team keeps Tyreke at the point, they could use an upgrade in defense and passing at the 2, and definitely need that guard to be able to shoot the three, create, and play off the ball. If the team moves Tyreke to the 2, they should look for someone like Beno but with a better outside shot and better defense. Who those players are, and if there's anyone out there like that we can get, I have no clue. But that's what I'd look for in regards to upgrading our backcourt...