So anyway, this idea from my last post likely has no legs, but I want to throw up a few numbers for comparison. This is assuming a max of Level 14 standard (BX or Mentzer BE only).
Level 1: 0 xp, 4d6 hit dice, spells 2/1, Turn S D, Z T, G T, Wi 7, Wr 9, M 11
Level 2: 12,000 xp, 8d6 hit dice, spells 3/3/2/1, Turn S D, Z D, G D, Wi D, Wr D, M T, S T, V 7
Level 3: 200,000 xp, 9d6+3 hit dice, spells 4/4/4/3/2/1, Turn S D+, Z D, G D, Wi D, Wr D, M D, S D, V T
Level 4: 600,000 xp, 9d6+5 hit dice, spells 5/5/5/3/3/2, Turn S D+, Z D+, G D, Wi D, Wr D, M D, S D, V D
Level 1: 0 xp, 3d8 hit dice
Level 2: 8000 xp, 6d8 hit dice
Level 3: 64,000 xp, 9d8 hit dice
Level 4: 360,000 xp, 9d8+6 hit dice
Level 5: 720,000 xp, 9d8+10 hit dice
Level 1: 0 xp, 5d4 hit dice, spells 2/2/1
Level 2: 40,000 xp, 9d4+1 hit dice, spells 3/3/3/3/2
Level 3: 600,000 xp, 9d4+5 hit dice, spells 4/4/4/4/3/2
Level 1: 0 xp, 4d4 hit dice, OL 30, F/RT 25, PP 35, MS 35, HS 25, CSS 90, HN 1-3
Level 2: 9600 xp, 8d4 hit dice, OL 65, F/RT 60, PP 65, MS 65, HS 55, CSS 94, HN 1-4
Level 3: 160,000 xp, 9d4+6 hit dice, OL 96, F/RT 95, PP 105, MS 96, HS 90, CSS 98, HN 1-5
Level 4: 640,000 xp, 9d4+10 hit dice, OL 99, F/RT 99, PP 125, MS 99, HS 99, CSS 99, HN 1-5
Call it 'Sweet Spot' D&D. Characters start out fairly competent, and can grow in power quite a bit, but it takes a long time to see any growth, so unlike the normal game, those who relish the 'level up' thrill won't like it.
A few things I might change around--no cap on hit dice (possibly only for Fighters), or go with AD&D die types for classes (Cleric d8, Fighter d10, M-U d4, Thief d6), and maybe giving Fighters double damage with any weapon at Level 3 and triple damage at level 5.