sketch vs feature
I agree with your assesment regarding certain part features (counter-bored, counter-sunk, threaded, holes and associated patterns but stick to my guns when it comes to simpler features such as fillets on revolved parts, and simple thru holes (and patterns) on extruded parts. The deeper the tree the more difficult it is to edit, and the more likelyhood there is of encountering (sometime in the design or editing process) problems, especially if the part has to be edited by someone other than the creator, a couple of years after it's created. I've witnessed no small number of instances where part trees have been so complex and or convoluted that designers have scrapped the existing model and created a new one from scratch.
Dependancies can arise in complex tree structures that will make editing a nightmare and make conversion of the data for use in other systems (not an uncommon occurance) virtually impossible or will result in a large amount of data loss. Just a few reasons to keep things as simple as possible.
Since everything we do in Alibre is sketch dependant it just seems more effective to develop sketches that approximate the finished part as closely as possible and then add those features we're not able to create at the sketch stage.
Now about the question that started this off, I sometimes take time out of my normal design work to practice building parts from detailed drawings. It makes you evaluate how the part can best be modeled based on the deliniated dimensional and geometric constraints. For anyone just getting started in Alibre 3D modeling, using 2D drawings to develope a few parts can help make the transition a little easier. Of course this is old news for seasoned users but sometimes we get so caught-up in the modeling aspect of our work that the drawing end of it atrophies. It pays to keep both as sharp as possible. One of the best texts I've come across for these exercises is Technical Drawing by Fredrick E. Giesecke et al. It can also give you pointers on constructing sketch features not offered as standard features in Alibre (ellipses and other assorted conic sections), as well as giving you a little history on technical drawing.