#1 It would be nice, not sure if devs would agree, but maybe expanded to 2 or 2.5 times current values 200m/250m Base, 40m/50m per Adv Squad Level, 20m/25m per basic Squad level.
#2 is one that has been needed for a long time, same kinda applies to stuff like demobs and suppressers it that highest effect should win, i'm not sure how difficult this would be to impliment.
There are a number of ways they could do #3, one option for it i'd like the see is the squad system overhauled, and sub-groups added, the squad or sub-group leader would have the option for which nexus effects they want in order of importance.
For example
Sub-group A Is made up of Ewar Mechs, Order of importance would probably looks something like:
Ewar > Speed > Shield > Evasive > Recharge > Locking Time > Locking Range>Everything else in no particular order.
While Sub Group B is made up of combat mechs, lets say they are speed fit, order would look something like:
Speed > Assault > Crit > Repair > Recharge > Shield > Evasive > Locking Time > Locking Range > Ewar > Everything else.
Of course they are just a quick ordering i came up with now, they are probably not perfect.
You could go one step furthur and have a personal or squad priority list.
I have some more ideas on the specifics of a squad management overhual that i may post at a later date.