I'm glad you enjoy the dogges. If you find those useful, you should see the ones with doggy senses. I can't make them work properly with the current version, unfortunately, so I have not released them. Non-weapon items don't get put in hands, so the scanner goes in the backpack.. I have a hacked solution to make it possible, if clunky and exploitable, which I could upload as a test mod I guess.
For tanks, a plasma pistol's mean damage is 52, that's 26 to 78 or 0 to 104 damage, depending on the formula you use. That means a starting tank is pretty safe using TftD formula, unless shot at the rear. Sides are also somewhat vulnerable for EU formula. But that's acceptable I'd say. The Alloy tank is immune to pistol shots except for the rear armor with EU formula.
For rifles, the alloy tank is still pretty much immune to the front and side with TftD formula (40-120 damage), but can be hurt more reliably using EU (0-160 damage). It should survive a salvo though. Heavy plasma is a danger later in the game, even with 130 armor, but that will be the point where you will roll out the T3 tank and T4 hovertank which will come with plasma resistance and/or heavier armor (gained from sectopod research).
I agree that tanks should be able to tank (and that weapons are a secondary concern), but it becomes problematic/exploitable when aliens can't deal with a tank and the AI is not willing to switch target. Players don't shoot cyberdiscs with pistols, RL soldiers don't shoot tanks with rifles, but we can't prevent aliens from shooting tanks with inappropriate weapons, so those must have the possibility to do some damage at least.
I am thinking of doing things such that a tank can survive a round of fire from a few aliens of its tier (starting tank vs pistol, alloy tank vs rifle, advanced tank vs heavy plasma). With the possibility to repair a tank hull, getting a destroyed tank is not really that dramatic. You lose the weapon(s) installed on it (~200k for more advanced weapons) plus repair costs and time. I think that's acceptable if it otherwise would have been a veteran (or a few).
Using a tank to save rookies in the early game is a different thing though. Sadly, rookies are one of the most expendable thing in XCom, except dogs I guess. But at that point, using (and potentially losing) the tank can be the only way to victory, which again makes it worth it.