NeoAnderson wrote:So do you think that his ability means that if a creature is unable to block it shouldn't be counted.
Following your meaning should be something like this :
1. For example I attack player B with Tromokratis.
2. Player B has 3 creatures (2 untapped and 1 tapped). He decide to block Tromokratis with the 2 untapped creatures.
3. Tromokratis lose unblockable, and resolve damage combat with the 2 creatures.
If the mechanics is the one above I think we can make a partial approximation.
We can Ask to the defending player at beginning of declare blockers if he want to block Tromokratis with all the available creatures. If he decide to block it, we can set Tromokratis characteristic : CHARACTERISTIC_ALL_CREATURES_MUST_BLOCK_THIS_IF_ABLE.
Your assumed mechanics are wrong compared to the text on the card. According to the text all creatures defending player controls must block it otherwise it can't be blocked. Due to this if even one creature is tapped then it can't be blocked, if
Tromokratis gets protection from a colour or creature that the defending player controls then it can't be blocked (because at least one creature won't be able to block). If
Tromokratis receives Flying or
Fear and at least one creature that defending player controls is unable to block it due to unsuitable conditions (doesn't have flying/reach or is not of the appropriate colour, etc...) then it can't be blocked. If does not allow for "if able" it is "all or nothing". So no we can't even do a partial implementation.
A tapped creature still counts as a controlled creature even though in most conditions it can't block.