Having played both, Haggis and Tichu are similar. Tichu does have the team aspect, so that does add an element of play not found in Haggis. Everybody guaranteed to have a bomb in Haggis is something not found in Tichu.
The timing of the bombs is a major issue with implementation here, especially in turn-based games. Not an insurmountable issue, but a major one.
Does the implementation wait for all people to specify "I don't want to play a bomb" after 3 passes (making it up to 6 days between actual plays in a 1 move/day game)? [[ Player A plays an Ace. Player B, C, D passes. D has a bomb, but thinks B also has one, so is waiting for them to play it. When they don't, player D decides to bomb. ]]
Does the implementation automatically skip a player if they don't have a bomb (letting everyone know the player has one if it pauses)?
Does the implementation allow an "I want to bomb if it passes 3 times" button, in which case both partners bomb the same trick?
Does it allow "I reserve the right to bomb," which smart players will always use (threatening to have a bomb even if they don't -- and if the option is not allowed, it reverts to the problem above of skipping players who don't have a bomb).
Side note for those familiar with Tichu but not Haggis -- Haggis only allows playing bombs on your turn, while Tichu allows playing bombs at any time. This is why Haggis does not have these problems.
Like I said, problems. This being the internet, someone is going to be upset with any implementation.
And, all of that being said, I'd still like to see Tichu on BGA
