Boltgun, thanks for confirming I'm not crazy to be so frustrated about this. And yes, TFTD is definitely a lot less forgiving than UFO (which is saying something). With no armor, I go through at least 10 dye grenades a mission trying to keep my guys alive. At this point I just want to finish TFTD so I can move on with my life, haha.
PS - You say armor isn't "crucial," but I am finding it impossible to win an alien artifact mission without it (playing Superhuman). I've failed three of them now.
Ah, see I'm too OCD to give up on a campaign. I won't stop until either I win or the aliens win. Unfortunately I can't win until I finish the research. And I don't save scum so my death count is very very high at the moment ... almost through the first year and the memorial wall has around 250 names on it.
That's partially true, but there are several important differences:
1) You can capture a Sectoid Leader at any point in the game fairly easily so it's not like Deep Ones which essentially disappear from the game.
2) While psi technology is nice, you don't need it to beat the game so not researching a Sectoid Leader won't hold you back ... beating the original game without using psi isn't that hard once you know what you're doing.
3) You don't have to research a Sectoid Leader to get psi, you have to research "any live psionic alien" so you can capture any Ethereal and also get psi tech. Having to research a live psionic alien to get psi tech is also logical where as having to research a live Deep One to get advanced armors and ship building tech is random and makes no logical sense (at least to me).
4) The information you get from interrogations in UFO straight up tells you that you have to research an alien leader to progress in the game so at least there is a hint that researching alien leaders is important (although if you opted for a Floater or Snakeman you wouldn't get the psi).
Point is, the UFO research tree is more logical and non-game breaking than TFTD. You can stumble around with research not knowing what you're doing in UFO and you'll finish the game just fine where as in TFTD, the research tree can stop you all together.