I share your opinion and I dislike how MoO was designed in this respect. Shields are not very good, costly and take a lot of space to be of any real use on SHIPS. On the other hand, the tech itself is quite important, because it automatically contributes to your Missile Base defense.

Mathematically, the problem lies in the fact that
a) shields can counter the weapon damage effectively only to cca tech lvl 10
b) or that every damage is counted as linear, as N * x, where N is the number of ships. If (for instance) the missile damage did N * x*x, than a shield reduction of 1 would make it (x-1)*(x-1), which is very effective and worthwile.


ECM is even less useful (but it contributes to MB's defense as well!). In fact, in certain cases it could be effective, but you never know what you get here.

Example: Let's say you can use ECM 1. The best effectivity comes when only 20% of enemy missiles would normally hit. ECM 1 reduces them to 10%, which means the damage is halved. But if enemy missiles hit in 50% of cases, then ECM 1 reduces it to 40%, reducing the damage only by 1/5. Quite a difference.


I think both shields and ECM can be effectively used on ships only when they are very outdated and very cheap - then I put ECM 1 or Shield 2 on my ships. It's really worthwile.

That leads into another question I've always had: what's a good way to tell when certain weapons are worth it? Is it never worth it to put newly researched weapons on ships (assuming you don't need the higher damage to punch through shields)?

What I'm trying to do right now is work out what the "best" weapons are. So far torpedoes seem crappy, shield halving beams almost never worth it, and disruptors the best beam.

No weapon is best - it is very situational. This is where MoO 1 outshines other games. ("It eats formulaic players for breakfast"). Some weapons are really good and in general, can win you the games. Missiles in general, and scatterpack missiles in particular, in my humble opinion, are a very good bet to lead you to a win (you make a missile boat with the 2-rack). They have massive punch at a relatively low price and no shield/ECM will particulary change that. Still, in certain situations they are harmless (against planetary shields or against Alkari minions) or can be countered by quicker missiles, HEF etc.

Beam weapons can be excellent if used properly (computers, high maneouver etc). However, until HEF they are usually second best to another weapon combination (if you can have it, which is never guaranteed in MoO).

Torpedoes are crap, sadly. Halving beams can be very good, though, WHEN they are a bit outdated. Neutron Pellet Gun is arguably the most useful weapon in early to mid game. You may use for a very long time effectively. Many lost positions were won with NPG.


When it comes to using new weapons / waiting for making them cheaper, opinions are divided. I've always waited for cheap/ miniaturization, but I have seen so many experienced players perform the opposite effectively that I doubt it is always the better choice. Again, situational.

Stick new weapons immeditely?
Cons:
- you don't get quick firepower (so when you are threatened by war immediately, don't use them)
- you stick less weapons on a design (miniaturization). Which means even over large time, you still pay more for weapons effectivity. I have not made the calculation here so I don't how much you lose.
Pros:
- you get your best tech on which can make the difference between losing / winning the battle (missiles - the difference in velocity -> first strike can totally change the outcome of the battle)
- you probably may punch through the planet defense better, which, again, can spare you a lot of losses

Long story short, for quick defense you may probably choose older weaps more often, while for attack the newer ones. Still, situational (isn't MoO a great game?).