On top of this she's so quick in her sabertooth form and not only can she traverse the map with great haste she can also use it to avoid a lot of damage and escape from tough situations.
During one of the invasions I had the enemy team almost finished. There were about 40 seconds left until they could respawn and the only person alive on their team was Ginebra who just outran me in sabertooth form for the entire duration. I could not catch her and the npcs were barely helping. If I shot she would just move from cover to cover, if I tried to melee I could not catch her. The time reset and they would end up winning which was really annoying because I actually played pretty well that game. They were on the 3rd round of respawning I believe (they had like 114 seconds on their timer). I just couldn't get that last kill.
Don't worry, you're not alone in this. I've had the same experience playing multiple characters, she has no existing counter.
I've had a lot of frustration playing with and against Ginebra. As a raider I have noticed Ginebras taking advantage of the high walls in A Breath of Hope (the maze-like level where you charge conduits) and just sitting there in cougar form, not participating, but also being unreachable for the antagonist. I also had a 40 minute game where I was playing as antagonist and the Ginebra's entire team disconnected after I triggered survive mode twice, but after it was just her left, she soloed the game all the way to the end by running from one end of the map to the other, killing engineers and triggering objectives where necessary. She's impossible to hit when she runs around like that, and she takes reduced damage, with no duration or cooldown on her movement ability. The 0.25-0.5 sec delay on shifting is negligible when she's on the other side of the map.
And to make matters worse, her crossbow is ridiculously potent, downing high HP characters in 1 hit.
This is just a poorly thought out character in general:
-Passive damage reduction
-Fastest character in the game with no limitations on her movement skill
-One of 2 characters that can climb up high walls
-Possibly the highest DPS weapon next to Shae's
-Only existing character with weapon knockback
-Stress is deactivated in cougar form, so she's undetectable in this form.
Unfortunately, fixing one aspect of her character, such as implementing a cooldown to her cougar form, wouldn't balance her - but they need to remove the wall climb, and max out her stress when she's in cougar form so that you can see where she is - you know, like Alicia, the only other mobile character that can climb up walls.