How would you explain that Keitaros girls are all high level espers? Especially someone like Mitsune, Naru a level 4 esper, seriously?
Let's not even mention Motoko getting into esper development, whatever for would she go into that when she already can use ki/chi in her art.
And this casual treatment of level 5s as some random powers makes me lol so hard.
Level 5s are rated by their general usability to Aleister:
1. Acellerator - Particle acceleration and manipulation is his forte, though at lower levels, so he can only do lesser things, like firing off things into atoms, flight, impervious to everything of this dimension, and even foreign to this dimension once he "partially awakens". Mixing in with magic subsystem he was able to match Hyouka and Gabriel.
2. Dark Matter - He wasn't shown much, since he pathetically finished in a fridge trying to become no.1. His remains now generate dark matter for various applications by Aleister.
3. Misaka Mikoto - Used for making of Misaka network, which serves for multiple AIM applications, the level 6 experiment was actually just a cover up for it.
She can manipulate electronic and magnetic forces, softer applications include reading electronic data as well as hacking/accessing electronic hardware without any hardware but her own power, has a personal radar field around herself, which also serves to block other things, like mental atacks. She can also magnetize herself to surfaces that are appropriate for that. And she can also fly by using surrounding water and stuff, can't remember what they are called now.
Offensive applications include lighting blasts, both directional and area of effect ones, creation of magnetic sand vibro blades which she can also lob at distance and control their trajectory, and then there is her trademark railgun, which she can use to varying levels. Railgun anime showed her firing off a large piece of hardware as her ammo, and some say that filler was approved by the author, but it is unknown.
She can even read memory, but she keeps away from that, well, mostly.
4. Mugino Shizuri - Breaks electrons down to fire beams or use the energy for shields, a bit of a mental case, burnt out arm in uncontrolled burst of her own power.
5. Shokuhou Misaki - Mentioned in passing by Mikoto as one of possible people she could go to to help Touma with his memory problem, but discarded her as someone she doesn't trust people around, as shown in Railgun manga. She is a telepath, she was shown to use a remote which she uses in some as of yet unexplained manner to manipulate her power to mentaly freeze masses of people, as well as alter their mental states.
6. Unknown
7. Sogiita Gunha - who is actually a gemstone aka naturally born esper, he is 7th due to his power being a bit of a wildcard. A lot of guts and shouting is involved in all applications of his power. Powerwise he could reach epic levels as noted by one of the strongest mages in story.
All the lower levels are kept at various levels according to usability as well, as some are useless or don't have that much potential anyway.
Hina girls would be mostly at max level 3 espers, and only some, and then there is the actual reason for them even being in the esper development program, Keitaro could be easily sent there as a gemstone with his high damage resistance.
Su has magical transformation during the red moon, she is incompatible with esper development program, unless you want her to end up dead fast?