Sven,
Although Whitemarsh Valley still plays up their George Thomas lineage, not much of what is there today bears his imprint, with the exception of the routing. In the first decades after the course opened, and again in the past decade a number of internal changes and outside architects were brought in such that tracing the internals of each hole almost requires historical CSI.
Both Ross and Flynn seem to have large impacts on the bunkering schemes, but in the past two years the club has embarked on a program to "make" the course "look" like a George Thomas creation by having Andrew Green of Macdonald & Company re-do every bunker in the frilly Thomas/Bell style and more importantly, take out all the evergreen trees (while maddeningly planting small deciduous trees in a number of areas) and expand green surfaces and fairway widths.
While the new, deeper, bright-white bunkers are either jarring or appealing depending on ones' tastes, they certainly appear starker on the landscape and therefore probably have a larger impact on strategy and play than the tired look of their predecessors. The irony of all this is that the earliest maps of the course (not sure if they were drawn by Thomas) show very little in the way of sand bunkers.
The green complexes throughout are varied and creative, especially with the expansion. The par threes are quite stellar, each of them noteworthy and each par five asks the player to make choices, almost always a good thing.
In the end, and no matter how many architects are brought in, Whitemarsh Valley is still limited by two congenital factors; the overall tight acreage of the property and the fact that it is indeed, a valley, with the valley floor having both drainage and flooding problems throughout the course history. Some of the recent changes have tried to mitigate those issues through creation of retention ponds and the building up of golf course features, presumably to stay above floodwaters from the creeks which affect play on numerous holes.
Still and all, there are many, many fine golf holes at WM, and in a tough neighborhood at least the revitalized course now has a cohesive theme and playability.