Just like every time - 3rd tier is the only one that has anything decent in it .. First tier has basically nothing of worth even for the 1 buck, and BTA is there just because they don't want to outright remove it.. (both are there just to make an illusion that 3rd tier is good, tricking people into thinking 3rd tier is very good in comparison with first two.. theres even a name for this in marketing cant remember though - works same with small, medium, large products/packaging. Small ones are there only to make you think the big one is such a good deal)

My bet is they will slowly start getting rid of it to only sell Choice style bundles where everyone pays 10-20 dollars for everything without any other choice.

Yes, a problem for the series is that when they release a new one it always feels like stuff is missing until they get around to complete the DLCs. But even so I found Tropico 5 to be weaker overall - less enjoyable than 6 (even with just the base game) and certainly not as good as 4 (complete). I'll get this bundle for the Tropico 6 DLCs myself, but newcomers may want to wait until there's a complete edition, or find one of the earlier Tropico's for cheaper than this weirdly priced tier 2.

The price shot up from $8 to $10 in a very short time, so it seemed inappropriate to add a third option when there's only two real prices.

That's because people pay more than the T3 price ($12) which makes the BTA tier (Tropico 4 + Tropico 5) overtake the old T3. Right now for example, the bundle costs $12.01 as opposed to $12. If more people will buy T1, the BTA price will fall back under $12 and the tiers will rearrange.

Kalypso wants you to know you're getting a great deal here 🥻

It's back to being T2, but as usual it's just 2-3 cents less than T3 so it doesn't make sense to differentiate them.

Well, it depends on whether the Tropico 6 - The Llama of Wall Street is included or not.
If it's included, you need to use sub/309465 (second entry in the list when searching for "El Prez Edition"), otherwise you use sub/309466.
The subs haven't been confirmed by anyone yet, so I can't tell which version is featured in the bundle but I am pretty sure it's sub/309466 since Humble Bundle doesn't like to deliver complete collections :)

By clicking on the gift link notification (without generating a gift link), but this has to be done before revealing the key, otherwise you can't see it any more.
Although keep in mind that the notification will show a list of countries even if the actual key you get is redeemable everywhere.
Your best bet is to check the OP of these threads, that's the closest you can get to a correct info - although I also make mistakes sometimes, since the info provided by Humble Bundle isn't always reliable. But at least you can see what kind of regions exist for a certain key.

Yup, thank you very much.