@Minezuki
(Sorry for late answer): Just a remark: OSO and Toaru have the same system. In OSO too the skill evolve. Even the number of equipped "sense" are the same. I am pretty sure that Toaru was made because the author was disappointed with how OSO turned out (Or the opposite) since there is too much similarity. Also, I prefer the slice of life in-game of Toaru than the slices of life IRL of OSO.
Edit: Reread OSO: there are 2 differences: 1) OSO has auxilary senses (+att; + perception, +MP, …) that Toaru no ossan doesn't seem to have. 2) In OSO, evolution are pretty important, especially for auxiliary sense (For example, you can combine +int and +MP into one sense), while in Toaru no ossan evolutions are just upgrades/specialization.
(Sorry for late answer): Just a remark: OSO and Toaru have the same system. In OSO too the skill evolve. Even the number of equipped "sense" are the same. I am pretty sure that Toaru was made because the author was disappointed with how OSO turned out (Or the opposite) since there is too much similarity. Also, I prefer the slice of life in-game of Toaru than the slices of life IRL of OSO.
Edit: Reread OSO: there are 2 differences: 1) OSO has auxilary senses (+att; + perception, +MP, …) that Toaru no ossan doesn't seem to have. 2) In OSO, evolution are pretty important, especially for auxiliary sense (For example, you can combine +int and +MP into one sense), while in Toaru no ossan evolutions are just upgrades/specialization.