If you are trying to specifically recreate the benefits of the old tree, you are understandably going to be very disappointed. If you have played on the PTS, you surely would have noticed already the huge change in the game play feel. Mechs feel tankier, run hotter, and lose weapons more often, just to name a few differences. What the over all game play changes translate to is a very different experience over all. Applied percentage changes will not directly translate from the Live server experience to the PTS. A side by side comparison of numbers alone however, does not do justice to the gravity of the changes implemented.
When you consider the PTS as a separate experience rather than trying to translate the Live server experience into the PTS, you can much more clearly explore the value and thought put into the PTS. Combat roles are introduced and given value in the new system. Investment in specific tech provides greater potential benefit than just placing the item itself on the mech to reap the full benefits. Scouting and infotech are by far the clearest examples of the new system's strengths. ECM for example, requires investment in order to get its full benefits, benefits that affect team mates more as they are invested in. Target info gathering speed, target decay, target retention... these are skills that are very useful, but not every single mech needs them if you have one or two players on a team providing that information for mechs that are more concerned with putting out damage. Auxiliary nodes extend scouting value by requiring an investment to provide improved intel gathering. These are things that are generically efficient across mechs in the live server. If the goal was to improve everything compared to the live system, we'd end up with a big jump in power creep as opposed to the PTS addressing power creep by providing a general nerf then allowing players to decide what they believe to be most useful to a specific mech and its intended use. If you need more examples just refer back to the spoiler notes, I've provided a lot in there.
TL, DR:
Don't try to recreate the Live system in the PTS, it leads only to disapointment.
Do look at it as a new system of how you upgrade your mechs from the beginning and consider the context of why PGI thought to place the nodes the way they did. That will allow you to see the thought, complexity, and value the new system provides.
Please offer thoughts and opinions, preferably with evidence or a thought out basis to it.