I was at a designers meetup last evening, they had a few points in regards to the new rule of Ace and King.

The original design of the mobility of each unit has a bit of a drawback to their strengths and give the opposing player one round to respond to the actions you take. e.g. a Jack is not connected to the back of his line once he jumps, unless you first place a card in-between to where you want the jack to eventually be - this give the rival time to respond; or in a scenario where you jump out with the jack without a supply line connection, you give the rival an opportunity to either take the jack and stop your incursion, or respond in some other way to how the card is used and for what reason it was used. All cards had this philosophy except the King which was the 'immovable block' that basically altered the flow of the battle with its presence. So when I changed the Ace and the King around just to make the Ace the most valuable card of the game so people felt right about the Ace in accordance to a standard card game - I also couldn't alter the value of the King in a meaningful way so there was both a risk and a reward of play with a turn in-between.

The new Ace and King rules were only tested a few times, and while the game felt acceptable in this form, it still lacked the strategic impact of the earlier design. Thus,

Ace is now the highest card of the game, simultaneously as it is the lowest card of the game once placed - reverting the rule with a slight adjustment (value going from 11 to 14). The King is back to being worth 13 and his original mechanics are back.

At the meeting, they also recommended that the games balance can be actively adjusted. You see, in chess, once you have played it a few times with a group, eventually you end up with one player winning every single time because they are simply better at the game. The good thing about games like MTG is that even while the better player should win a lot more games, there is always that small percentage of luck involved in letting a worse player have a chance at winning albeit slim - which makes the game more intense and fun for most people My game has the same benefit of being mechanically bound by the draw of cards. But, the balance can be further optimized by limiting choices for the better player. So a beginner player plays with 5 cards on hand, while an expert plays with maybe 4, or 3 cards, depending on difficulty level. As that limits the choices from 5 down to whatever number on hand.