Your WPF code will need to be in C# or VB to get designer and tooling support. Interop between C# and C++ is very good via the use of mixed mode assemblies, which allow you to code a module in C++ that compiles to a mix of managed and unmanaged code. This gives you type-safe interop to your native C++ libraries.
See here for information on mixed mode assemblies. We can vouch for them.
One important consideration IMO is the WPF learning curve. If you can bring your team with you I believe it can be extremely productive.
