But the barriers to experimentation are the same as with ship weapons - you do the engineering, and if you don't like it, buy a new weapon and try again. It is a bit more complicated because you cannot combine engineering on ship weapons
Theoretically, yes, but in practice no, I think.
The loadout on a ship is made up of 20-30 modules, so if you decide you don't want a particular modification, you can replace that module and the rest of the ship still stands.
You can also change the experimental on a module without losing the main modification, so if you make an overcharged corrosive weapon and then decide that the effect on the ammunition pool is too much, you can switch it to overcharged autoloader for only the cost of the autoloader component. Sure, if you want something other than overcharged you have to start over ... but still, only on that weapon, not the entire ship. And you've still got an overcharged corrosive for later if you find another use for it on a different ship where the ammo pool is less of an issue, of course.
A fully-engineered suit or weapon in Odyssey has eight components, all of which are stuck together. So a full loadout (suit + 2 weapons) needs 24 upgrades - not dissimilar to a ship - but with the ship you can swap out any of those 24 without affecting the other 23, whereas for the loadout you have to swap out an entire block of eight to try something else.
It's not so much of a problem when doing your first loadout, but it's quite a barrier to making further adjustments and experimentation because you can't really compare if G5+A+B+C+D or G5+A+B+C+E is better on a Aphelion until you have both set up (a pre-bought G3+E will clearly be worse, but that's not E's problem). Whereas with a ship, sure, you'd need to engineer up a new 'E'-blueprint module for that slot, but then you could swap it back and forth with the 'D' at will, or maybe if it's weapons have both the D and E at once and swap the B for an F with little marginal cost ... whereas G5+A+C+E+F would be yet another "start over" in Odyssey.
Obviously if you enjoy the Odyssey base-visiting/missions content then it's not a problem; if you're more interested in CZs or Exploration, then those don't give materials.
Module rating is hardly the equivalent to suit and wepon engineering.
It kind of is, for a lot of modules.
E to A FSD more than doubles your jump range.
Unengineered to G5+Mass Manager is less than double.
E to A power plant is 50% more power.
Unengineered to G5 Overcharged+Monstered is only 47% more.
A-rated shield generators are more powerful than E-rated G5 Reinforced.
We're just at the stage now where cash is easily available enough to buy A-rated automatically. And, of course, if you don't like an A-rated module, you can sell it for all your credits back to buy a different A-rated module.