(To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there.) The value of X is determined only once, as Tromell's last ability resolves
In addition, the foil version of these cards can show up in the guaranteed foil slot (along with a plethora of other opportunities)
You only have to take a look at the downshift of rarity in Hero's Downfall to see that clearly, because MTG is changing at a rapid pace
That gives you plenty of mana sources in your opening hand without worrying too much about land-flooding later
For starters, the sacrifice effect is cheaper, and not tied to colored mana
This flies in the face of the argument that occasionally comes up from the MTG Finance community (many of whom have a vested interest in the Reserved List) saying we should simply stop talking about the Reserved List and accept its currently detrimental impact on the game