IMO the real hard part of TT is the actual obtaining of the cards when it comes down to it. Poor RNG reward of cards from winning TT matches along with poor MGP trade in/buy ratio values are the present issue.
Example: Go play the imperial 300 matches for a single Gaius card and you come out with around 27000MGP and then trade in the 40 Livia & Rhit cards for 10MGP and the 20 Nero for 50MGP and you get a small bonus of 1800MGP (not even enough to buy a single gold booster). A total of about 28800MGP~. Sure that's enough MGP to buy a minion/barding/few other things. But looking at it from the TT side of the MGP pool it's nothing. Now you can take all that MGP and buy around 12 gold booster packs in hopes of Zidane/WoL. Instead you get about 5 Miounne/Gerolt and another 3 Momodi, and 4 Tenfingers. Trade all those cards back in for 10MGP each and you got back a whopping 120MGP. Who knows tho you could have gotten super lucky and gotten Cid/Ultima but if you already have those cards then you get back only an extra 200MGP added. Not even enough to buy another booster pack.
The game is meant to be a fun side challenge but it's turned into a super heavy RNG grind challenge. The NPCs are fine in all honesty, they offer a challenge and aren't impossible or insanely difficult to beat. The cards however imo should not be heavily RNG obtained when they have little to no MGP value, let alone even the 4/5 star cards since we can only use 1 of them at a time in a deck. It would be nice if the TT game implemented the pick a card that you flipped if you win the match/obtain all the opponents cards if you flipped them all feature. That feature would not make/break the game at all, and it would allow players to pick cards and greatly help them in building up their decks. The Platinum cards can still keep the hard to obtain function but not as heavy as it is atm, Plat booster packs have them but at low % RNG. The instance fights have them but could increase the RNG because 40-70 fights is a bit much. And even with NPC's by making it where the NPC doesn't use the Plat card 100% of the time in the deck so people couldn't farm that card specifically for MGP gain. But allowing us to always pick one of the cards that give us 5mgp-200 MPG is not a game breaker when it comes to earning MGP. Let alone since players are spending around 2,160 MGP per gold pack with a 95% chance to obtain a card with a 10 MGP value turn in.