I think you already know my answer--Yes PowerShell has been neglected in SQL Server 2008 R2 with almost no changes and we can only hope we see changes in Denali. In Denali we've seen a hint of several new cmdlets for managing HADRON. I think six HADRON related cmdlets were mentioned by various bloggers, but still nothing that covers basic-level day-to-day DBA tasks.
As for SMO, I don't have many gripes. Having spent considerable time working with SMO and other object models I feel that SMO is a wonderful object model. Yes, there are pieces of SMOs that are slow and yes there are a few pieces missing (easily remedied by adding synthetic properties using PowerShell), but this is nothing compared to other SQL Server related technologies (AMO, RMO, SSIS, SSRS). These areas have zero PowerShell coverage and some of their object models are difficult to use. The one that gave me the most pain was SSIS. The SSIS object model is clearly ported from a COM interface (several methods that do similar things differing in parameter types). In trying to use the SSIS object model there are things not exposed outside of SSMS which I find very annoying. Manageability seems restricted to the core database engine and very few DBAs solely work with just the core database engine.
One of the promises PowerShell makes is that as an administrator you'll have a consistent way of managing systems, but this only works if they build coverage.