It isn't feasible to shield every planet/system, that's using up maintenance points better spent on fleets and troops. Fleets (or even just squadrons of X-wings) are more useful since you can move them. Shield generators without an accompanying ground force and fleet are just begging to be sabotaged.
Totally feasible. You're already garrisoning with troops, adding Gencores ontop of that is only like 15-25% more overall maintenance. Though maintenance isn't usually the problem in MP, its refined material, but they aren't too out of line.
Assuming two Gencore mk1s, that's 80 points of shield rating. B-wing\TIE bomber\Y-wing squadrons are 2 points each, SDs are worth several points and the best at bombardment. So more like 5-10 ISDs depending on what's loaded in their hangar bays. Not many systems start with 2 generators IIRC, usually it's just Coruscant and a couple of random ones in the core sectors.
Yeah but bombers are trash that noone uses unless they want to suicidally throw away a fleet. Attack with 10 ISDs loaded with 60 bombers and 12 x-wing squadrons would probably destroy your whole fleet. So instead you have to take TIE fighters/interceptors at which point ISDs themselves only have 2 bombardment strength.
I mean, sure, you can create a special group of 6 escort carriers with 36 tie bombers (cheapest way to do it). Then you are looking at a total of about 340 maintenance in order to bomb through 24 maintenance worth of buildings (and frankly by the time you are able to throw this many squardrons into a bombing role. the enemy should have gencore 2s which just laugh at your shit). And your fleet is almost useless for anything but bombing. Eventually you can get tie defenders that are actually useful units, but that's a shit ton of the most expensive squadron in the game at only 1 bombardment a piece. Rebels can at least sort of bomb through shields with mass X-wings + B-wings late game, but its still mostly just a theoretical advantage, by the time you can amass such a fleet you can probably win in a dozen other ways.
Bombarding a 100% enemy controlled sector isn't an issue loyalty-wise, and you can render a planet totally unusable (Base Delta Zero style). There are also a couple of exploits people sometimes use in MP games (HQ colonization and ghost fleeting).
Yes, obviously this is the point where you build Gencores. By the time you have 100% control you probably have a construction planet that can crank that shit out.
If there are enough troops and a General there, you'll have a very tough time getting through undetected. Though if the planet's blockaded and relief isn't arriving, it's only a matter of time before you take it anyway. The AI isn't great on the strategic level, but it does relentlessly use spies and saboteurs against you, and garrisons pretty well.
If you throw 3-4 decoys into each mission you can really get through anything just fine. And when you can just sabotage your way through multiple gencores and 10+ regiments in about 15 days its kind of silly.
Tarkin in the ANH novel mentions 1 million systems, and at it's height the Empire had millions of starships (with at least 25k being Impstars - 1 of which can slag an unshielded planet). Obviously it's difficult to show this kind of scale on a movie budget, so it's mostly in novelizations\EU and background materials. I don't mean the game needs millions of ships, but the number of structures per planet was a little on the low side. 200 systems is an okay abstraction, but they should be able to support more ships than they do. The travel time between sectors is far too long, resulting in a very slow build-up (even worse if you don't start with a construction yard).
Structures per planet is just an abstraction, if you made it 10x as many that were 1/10th as strong it wouldn't change anything. Travel time between sectors I like, one of the very unique things about Rebellion that forces a long-term mindset.
How many ships do you want planets to support? Average planet gives around 200 maintenance points. An ISD with fighters and troops only costs around 100 maintenance. Frankly I don't think I've ever actually hit the maintenance cap in a serious game.
Yeah, the not-starting-with-construction-yards thing is totally lame. If I remade Rebellion today I'd do something like make it so each core world planet has a built-in construction yard that can only be used to build things on that planet (i.e. not build structures to be sent elsewhere).