There is 0% chance that Senna abilities remain the same 2-3 months after release

Senna's abilities were just released, and she looks quite fun to play. Being the first "ADC support" she looks quite different from what has come before, which could be great for Riot to experiment with newer champ designs. But that being said, there is zero chance that her skill set will not be nerfed within the first 2-3 months of her being released. 4 months maximum, and thats only because she is being released right before the preseason, so Riots balance team will go into hibernation until the Pro circuit starts up again.

First off, Senna is a hybrid of 2 classes. Support+marksmen. Hybrid champs have never been unbalanced, such as or who Phreak aptly described as an "artillery assassin" upon her release. Riot has also admitted to making new champs and remade ones more powerful on release, and then tuning them down after the community builds a player base around them. This often involves removing parts of the kit; see

Now on to Senna herself. Her passive says that she is "slow to fire, but deals bonus damage" (ie what Caitlyns kit should have been.) Being a support, Senna will lack the gold to get an ADC build, and so will naturally be able to gain AD, crit, or range. IMO, the range generation will probably be gone in the future, as she appears to have level 18 tristana if she picks to start upgrading that, which appears to also affect her Q range. A snowballing Senna will only stomp harder, as she will be harder to engage upon when she is autoing you from so far away.

Her Q heals allies and damages enemies, it seams to be the skill she would max first. It appears similar to a xerath Q, but shoots faster and without the charge time. Senna can also use it to heal herself. IMO, the self heal will most likely be stripped from the kit in the future, and the cast time could possibly be delayed, it just depends on where Riot will address her kit in the future.

Her W is a skillshot that can create an AoE root after a delay. This is probably the one thing that Riot could leave in her kit, but they might remove certain aspecs of it if they decide to nerf her CC over her damage.

Her E is going to be a pro balance nightmare. There is 0 chance that this skill is not heavily nerfed/changed in the 2020 season if Senna ever sees pro play. The mist follows her and camouflages allies in the mist, even when they leave they appear as a specter. This opens up mind-boggling out-play potential with swapping champs in and out of the mist so that you dont know if you are being chased by the enemies engage tank or their fed assassin. This is by far the coolest aspect of her kit but it will 100% be changed/nerfed in the 2020 season

Her ult is what you get when you meme your ADCs Ashe/Ez ult one too many times. A wider than the lane global "skill" shot that has insane travel speed, it provides a shield to allies in its enormous radius, and can land a kill for more skilled marksmen with the smaller linear skillshot. This is 100% guaranteed to lose its global range at some point.

Senna is just another case of Riot releasing a champ who is blatantly going to be meta defining upon release, and have to go through rounds and rounds of nerfs until she finally hits a balanced state after having received major cuts to her kits design. People will still call her bad on release though when she has a 46% WR for the first week because people are dog-shite at playing new things in this game