Humans could be made stronger by training or elemental attunement - if we assume the pre-buffed Lycanthrope is your ordinary peasant, then cards like Crusader and Graviton Mercenary make a lot more sense as they're probably professional soldiers. One could even reason than an Immortal is an Ascended human of sorts.
Taking the idea of empowered humans a step further, we have things such as
Knights,
Sages (Page is slightly broken due to forum porting), and
Mages.
Overall :
Average Peasant / Civilian : 1 ATK | 1 HP , No Ability
Professional Soldier : 2-4 ATK | 3-5 HP , may have an accompanying ability with justification.
Attuned Humans/Spellcasters/Typical RPG Adventurer : Varies depending on the ability for balance reasons. As a rule of thumb, these cards would probably not be greater stat wise than a dragon.
Undead : Varies, as we've seen Skeletons with 1 | 1 and Ghosts with 7 | 4. Ability would also vary.
From generally observing how 'humanoid' ideas have been posted on this forum, most 'normal' humans will not be able to outmatch a Dragon, and empowered ones still generally have a disadvantage in terms of RPG-ish 'stats'.