That is constructive critisism. Constructive critisicm against your solution but that doesn't somehow invalidate it. Without a working solution, the idea is useless, isn't it?
Replying to your "thats constructive critism". I can lash out with critic like that too: Aliens have so much better weaponry, instead of invading a base, why not destroy it with a giant plamsa blast from outer space? BOOM. Instead of a former base is a huge crater left in the ground. because aliens are smart. they try to invade it, get shot down, so they destroy the whole base. thinking as an alien who wants to eliminate the threat. and no, they don't need to get someone alive or steal our computers to get some data or something. their technologie is superior, they have no interest in ours, so they can destroy it without regretting it.
and yes, if you may say "but the base is faar deep under ground", i would say "oh, that giant super plasmacannon, invented to quickly destroy defenses of resisiting planets, can sourly blast a few miles deep whole into the ground".
due to exaggeration and fantasie we can find arguments against or for anyhing. so now i am arguing complety AGAINST BASE MISSIONS.
because aliens don't need to take the risks. when they figured out where the opponents base is, they can just destroy it.
so now argue with that!
you can't say aliens wandering throug space, eliminating every race on every life-suitable planet they meet, didn't had any resistance before, where say needet a bit bigger canon, can you? ;
Now next to your argument (mhm, if i say something wrong or so, dont take it personal, my english s not that good and i am having this conversation with fun)
I am talkign only abour base-defending missions, other missions are not affected:
there may can be an element of suprise, or as you tall it my solution takes away much of the tension. But in my opinion wild goose-chases are absolute less fun than seeing your enemy and having the chance to slaugther them.
you have enough tension during the game. there are landed ufos, crashsites, missions and and and. everything fine with tension and stuff.
and like i said in one of the posts before:
you should be able to research "improved base defenses to invading aliens" after your first base mission. reason for that? "Hell no, we didn't thought of aliens entering our base... we have rocket defense, lase defense, plasmadefense... we never thought of they might get through. but they did. soldiers reportet that there are lots of spaces where they could hide, it was hard work to find any alien. after this first base entering of the aliens, we gathered our scientists how we can improve base security: they suggestet to....."
so, if you don't like the idea, you don't need to use it if you don't want to. when you want your base defense missions you don't need to research "improved base defenses due tu invading aliens".
in my opinion, why i came up with the idea:
there are a loads of missions to do, they all have their fun to discover things. but basemissions are way to repetive. after 20th basedefending it gets soooo boring and its really annoying. and no, after 20th basedefending i dont need "tension" or "element of suprise". the mainpart of the game is not to defend your base in hundrets of missions, its aim is do defeat the aliens. and rescue earth. but you can't move on with the rest of the game, when you have a basedefending and a base defending and...
i mean i don't want to cheat like every alien is visible all the time in every mission, thats not my point. i'd like to have a way to ease up base defense missions a bit.
but ok, you don't like it - and still got no arguments :-p