New Android smartphone - recommendations

I am aware that this question might also be suited for the Hardware-page, but still I feel it fits better in here.

I am currently looking for a new smartphone, since my Moto G of the first generation gets a bit slow sometimes. The following points should be met by a replacement:

• obviously, it should be an android-device
• it also should either come with only few mandatory apps, or be rootable
• probably most restrictive: I want the phone not to be too huge, 5,5" tops
• I want to spend about 250 Euros

Is there any device out there which meets my criteria and is probably reliable enough to last at least three years?

I like the new Xiaomei's, but these are quite large.