Please don't change dianas e
Here's why. This will take some defensive power away from Diana and screw her ability to slow a champion down. For instance if garen uses his q to close the distance you can get him on the outer range of dianas e and use it to slow him but he also doesn't get close enough to actually hit Diana. With this change you will be inadvertently buffing any champion who tries to get in some auto attacks. Another example is hecarim. You can e to slow him down to the place where he may not being able to e you or at least it will deal less damage. For the most part if Diana gets in on a squishy target they are going to flash out anyways. This is more of an overall nerf for Diana than anything else and a situational buff.