Hi Xaviju,
Great work so far! I would definitely recommend actually using a copy of either 0.91 pre3 or a build based on trunk for your evaluation. Simply put, 0.48.5 is just a bugfix release in the 0.48.x series... so there are no changes to the feature set in your copy for 4 years. Needless to say you probably can't get a good feel for all that has been worked on by just reading release notes.
In one of the documents it mentions "Room for improvements on gradients", and there have been many improvements for the Gradient Tool in 0.91 (with complimentary improvements in the Fill & Stroke dialog). Likewise, that document also mentions "Room for improvements on groups & layers management" and in trunk there is a new Objects dialog which likely addresses a number of shortcomings in the Layers dialog that you see.
So, that's my recommendation... please check out 0.91 or preferably a trunk build so you know better where things stand.
Cheers, Josh