I think building from MKXL is a strong idea, since the game was clearly very popular and, towards the end, had cleaned itself up quite a bit. I had a few qualms with how it played, but I think it would only be a few tweaks from being a little more complete.
-Run is still in, but it is just a forward-foward input. There is
NO forward dash - only run. There's still a stamina bar that depletes while running. Running has a small bit of recovery before it can be canceled into block, but can be immediately cancelled with jumps or normal attacks. The idea would be that running forward will still be used as offensive maneuver, but it's not entirely safe to just get in with if the defender reads it.
-Backdashing doesn't cost stamina, but it's now only invulnerable when used with
reversal timing
. The idea would be that it could still get out of gaps in strings and be used as an escape on knockdown, but not when done raw, as a means of avoiding degeneracy
-Designated specials can be made invulnerable as you are getting up, just like Injustice 2. Delayed getup disables the wakeup timing necessary for the specials to become invincible and has two timings using the stance switch button, also like Injustice 2
-New mechanic meant to stop degenerate use of really low hitting d4/d3, and machine gunning d1's that is very similar to Tekken's Low Parry. Hitting down/forward without holding block will "parry" attacks that are flagged as crouching or lows. Upon a successful parry, the attacker is put in a combo state that is prone to heavy scaling and limited gravity. The idea would be that you wouldn't get an incredibly damaging combo, but now have a high risk/high reward option to stop people that are constantly trying to low profile, abusing really strong d1 frames, or try to d2 you out of your throw/high attempts. On the more geeky side, you'd probably have to fudge with it a bit so you can't O/S crouching attacks and low parry
-As far as variations, I would tweak an idea from Persona 4 Arena Ultimax that saw each character have a "Shadow" version that played by different rules. For a new MK, I would imagine you could create some lore reason to have a "Kombatant" and "Revenant" version of each character that look dramatically different as they did in MKX, as well as have different specials, strings, and move properties. The idea would be that depending on your style and some matchup quirks, you could choose the Kombatant or the Revenant. As far as those differences:
- Kombatants are fighters with a keen sense of how to control the battlefield. They have access to Block Breaker, "Weapon Attacks" (Think moves like Cassie d2/B2, Ninjitsu Scorp f2/b4, etc.) and a projectile. This version typically has better options under pressure, better AA/ranged attacks with weapon strings and attacks, and can put something on the screen for other characters to deal with
- Revenants are those who have given into their own lusts for power by embracing the Netherrealm. They have access to unique armored attacks, "Forbidden Arts" (typically more mixup type strings and specials) and have more health and less damage. This version is a character who may struggle to advance past projectiles and strong neutral, but has more health to soak up damage and far better mixup options up close at the cost of less damage than a Kombatant
-I agree with most everyone about the aesthetic going back more to the 70's Kung Fu style of MK9 and before, although I didn't mind the darker look for MKX.
-I think I2 style loot system but centered around the Krypt as a constantly evolving force much like The Multiverse would be really awesome