The following is a list of limitations that are actually caused by limitations of the Flash format:

Line cap
in Flash the line cap is not configurable, the one and only choice is "round cap". In SVG the line cap is configurable, and the default is "butt cap".
Gradient spread
in SVG you can configure the gradient spread method (pad/reflect/repeat). Flash only offers the pad method, hence all gradients are padded. I have tried emulating repeat/reflect gradients by creating a gradient that repeats the stop colors a number of times, but I quickly ran into the limitation of Flash that you can only have 8 stop colors per gradient.
Gradient stops
Flash only offers 8 gradient stop colors, SVG allows any number.


The following examples are actual test results: