The Tiger P is alright. It's a fairly balanced T7, last I checked it had decent server winrate. The VK A needs a bit of retooling (To be specific, gun depression) and the VK B needs to be given an actual role besides "shitty E75". They could do a lot of stuff; better ground resistance would give it a mobile fascist box feel. Side armor buff would make it noticeably better than the E75 at sidescraping. You could greatly buff the 128 to give it more of a support feel. You could buff the lower glacis to give it more of a homogenous armor scheme and create one hell of a T8/T7 bully. Anything. It just needs a role.
I wrote a little snippet over on WoTLabs about what tanks I think are worthwhile to have in your garage for the sake of fun. Might help give you some ideas. *shrug*
My grand list of everything worthwhile in this game:
T1: Leichttraktor (Vision games)
T2: BT-2 (Best P:W in-game), T18 (High RoF 1-shotting cannon)
T3: T82 (Largest cannon for tier), Pz. 1 C (Mauser), UE 57 (By far the best camo/view combo of any low tier)
T4: T40 (Great cannon/sight/mobility package), UK Matilda (Best T4 when it gets there), Hetzer (Best 105mm chassis, armor, camo), T-28 (Incredible for mobility/firepower lovers)
T5: T1 Heavy (Ramming + Frontal Armor + Good Firepower = Fun), KV-1 (OP az fuk, multiple viable guns to keep you occupied, armor), T49 (Best Mobility/Camo/Firepower package), AT-2 (Best armor in-game, arcing derps over hills), ELC AMX (Great gun on an incredibly fast, invisible tank), S35 CA (2nd best per-tier alpha)
T6: Hellcat (T49 w/90), FV304 (Fastest SPG + Great Camo/Size/Arc = Fun TD), KV-1S (Best mid-tier gun/mobility package), A-43 (Best DPM/mobility package)
T7: T29 (Best turret armor, good gun+survivability package), T71 (Best Scout/Firepower package), AT-7 (Great gun+armor package), SU-152 (Great camo+alpha package), T-34-1 (Firepower + Camo + Armor on a med)
T8: JP2 (Mobility + Firepower without major sacrifice), Rhm.-B. WT (Turreted + Firepower + Camo = yay), AMX 50 100 (1800 spike in a tier with 1200-1500 HP tanks?), Obj 416 (Imagine the ELC made into a T8 med), ISU-152 (Incredible and reliable firepower w/camo), IS-3 (Speed/Alpha heavy w/great tourn/tb/tc viability) WZ-132 (Best scouting LT in-game)
T9: T54E1 (Incredibly fast spike on a chassis that can easily use it), T95 (AT-2 esque armor without the firepower issue, 10k+ potential games allday), Tortoise (Best DPM in game, can actually use DPM), E-75 (Best heavy armor abuse, mobility to use it), Foch (Best TD armor abuse, mobility to use it), T-54 (Best all-rounder), WZ-111 1-4 (Mobility+Firepower heavy without major sacrifice)
T10: All except IS7, IS4, M48, FV4202, and T-62A.