Here you can find a criterias used by us to divide maps by difficulty. Of course these criterias are subjective.

Easy

Player can use 1 or maximum 2 strafes
Requirement of 270+ prestrafe is required
Easy bhop without stand-up
Examples: bkz_goldbhop, av_degyptianez, bkz_junglebhop, cg_lighthops

Easy-Average

Skill to gain up good LJ prestrafe
Enough skill to make 2-3 strafes
Enough skill to jump 240 LJ (not on lj-block)
Have basic knowledge about CJ
Stable prestrafe with ordinary bhop
Basic knowledge about Standup Bhop
Examples: cg_wildwesthop, j2s_4floors, kz_goldwood, kz_j2s_cupblock

Average

LJ 245
Enough skill to make 4-5 strafes
Basic CJ skills (about 250)
Basic Standup Bhop skills
Examples: kz_kzdk_covebhop, cg_brick, cg_arizonabhop, fu_bhop, kz_hop

Average-Hard

Max LJ block - 250
CJ skill at least 250
Middle skill for standup bhop
Examples: kz_adventure, j2s_4tunnels, bkz_goldbhop_h, kzru_pharaonrun

Hard

Good 5 strafes
Enough skill to jump 250 LJ
Enough skill to jump 255+ CJ
Middle+ skill for standup bhop
Examples: ccn_scourge, cg_d2block_h, dyd_progressive, holy_lame

Hard-Extreme

Examples: fu_extreme, hb_ShoCk, kzpf_deathless_x, kzru_technology_x, kzz_bhop

Extreme

Examples: hfr_apex, ins_lab_h, kzz_prison_x, kz_kzru_MIR

Extreme-Death

Examples: kz_synergy_x2, hb_lrs, kzray_extremebhop, kzro_brick1337

Death

Examples: gbc_script_x, hfr_hb_toffifee, kzro_bhopnslide, kzua_mk_posteriori_d