Dragonling Mechanic and Razorfen Hunter aren't terrible.
They are, though. They're not even playable in Arena. If you insist that you're not going to pick one of top 8 classes to play with basic cards, though, it probably makes sense to go ahead and stack some other bad decisions on top of that one, I guess, so run 2 Wisps, they combo with Bloodlust.
Re:Neptulon
Neptulon is actually not that great, he just happens to be in the subcategory of card Shaman is dying for. Shaman has lots of ways to use small amounts of mana to get strong effects: Stormforged Axe, Hex, Lightning Bolt, Forked Bolt, Earth Shock, Rockbiter Weapon, Earth Shock, Rockbiter Weapon. What shaman didn't have pre GVG was any way at all to refill his hand after dumping all those cheap cards. All control shamans were running 2 Azure drakes and wishing they could run 6, because after dumping those cheap minion control spells you just want to refill your hand and win endgame. Neptulon draws you lots of cards. From another angle, Neptulon makes use of about 18 mana crystals on average, which is even more than Ysera with optimistic expectations for her lifespan (Ysera would be a great solution for Shaman if they didn't run out of cards so fast, it's easy to have one card left in you hand on turn 8 and apply to the bank for a loan wanting to play Ysera)