A lot of good observations and thought, @Kurungu, I wholeheartedly agree with almost everything and I want to specifically mention the health bar issues. I completely agree that having the detailed health and armour info right off the bat is going against the spirit of fighting an unknown, alien threat.
I do understand how some tactical game aficionados always strive for having as much detailed information about combat situation as possible to make the best possible decision but in case of XCom games(and I use this term loosely here), fighting the unknown threat, making the best of what you know and learning more through research is a crucial part of what makes those games unique and appealing.
I do think that outside of basic human opponents, well-known human vehicles and tech(i.e. mutants and experimental tech fall outside of that category), enemy stats should not be available to players unless particular enemy is researched. Information starts as “healthy/lightly wounded/severely wounded/dead” and “unarmoured/lightly armoured/heavily armoured” for unresearched enemies. Researching a body part provides detailed info for it while having more than 50% of the enemy body parts researched provides the detailed info on the enemy total health.
As for new player experience, firstly I do not think the game should extensively cater for inexperienced and, more to the point, those unwilling to learn. XCom-like games were always quite hard and quite complex; those qualities are an integral part of what makes them appealing, what makes them stand out. So a good tutorial and detailed “ufopaedia” articles should be much more preferable that an overbundance of easily available tactical information with no efforts required to obtain it.
Now, how I think new player experience as well as veteran experience should be tackled. My solution is to tie the stat information availability into difficulty settings. While basic selection of “easy/med/hard etc” difficulty levels should provide a quick way of selecting a difficulty, all(or at least some) variable difficulty settings should be available via advanced difficulty options, similar to how it is done in Long War. Each “base” difficulty setting will have a pre-set of advanced options with a difficulty score indicating how selected difficulty mode relates to pre-set modes.
Easy mode will have “research required for detailed enemy stats” disabled by default while other pre-sets will have it enabled. Players will be able to either pick a pre-set which will cater for their overall idea of difficulty or, in case of a experienced player who simply prefer having the full stat info right off the bat, pick a difficulty and then tweak it via advanced options. To keep the difficulty score at the desired level(i.e. custom but still qualifying as “hard” for instance), other difficulty options could be enabled to compensate for the additional stat info. This will solve the new player experience issue for those who will be unable to deal with the lack of start right away.
Now, to make things interesting for seasoned veterans, who are on their Nth playthrough and could already memorized all alien start, we can introduce and additional difficulty option to slightly randomize the stats for each alien body part at the start of the campaign. I expect this to be in line with the overall feel of the game as randomized alien composition from a library of body parts is already being implemented, this idea only takes this a step further, if not envisages the already planned but not yet announced feature. Stat variation have to be limited, of course, to prevent aliens form being impossible to kill early on. But if implemented as a pick out of 3-4 stat pre-sets for each alien body part, instead of being fully random, it can go a long way to make stat research meaningful even when you have several playthroughs under your belt.