Hi Pup,
Let's try to ease some of that sufferin'.
Master computers, especially at higher tech where they weigh less, are very useful.
1) larger hulls require more crew quarters and life support. so even at level 1, a 40kt Master Comp can be worth while over 10kt Bridge, 2x10kt Crew Quarters and 2xkt Life Support (50kt total). when the Master Comp only weighs 30kt or 20kt, it saves you lots of component space.
2) the Master Computer can be THE defense against some weapons (special tech weapons which I'll leave unnamed for your future enjoyment and suprise) which only effect crew.
Proton Beams, Meson BLasters and some other *initially* useless *looking* weapons can also be very useful.
1) you did not consider rate of fire. using a well armored or well shielded ship with a bunch of beam weapons can be devestating against an opponent using nothing but high-damage, lowe rate of fire weapons.
2) at higher tech levels you do get more range and keep that nice, 1 rate of fire.
3) a strategy you may be missing is that you can concentrate a relatively low amount of research to get a generically useful collection of beam weapons to use vs spending larger amounts of tech to get some other weapon types which could do more damage per kt, but fire slower or have other limitations such as the targets they can hit.
Responding more specifically would be easier if I know what other weapons you are comparing them against.
Ground Troops. Try setting the ships strategy to "Capture Planet".
Also, the full game will have documentation. A strategy guide would be harder. This is due to the fact that so many strategies can work, depending on how they are used, who your opponents are, and what game options you have set. SE IV has such a rich tech foundation that there truly is no "single strategy" that I've found always beats everyone.
I hope this helps,
John