Wellone ability is a bit naff even if it is "I can turn into a CR 1 baby dragon" so what else would you have a shapeshifter do at early levels?
its also going to be really unbalanced theres really no way for a Level 5 Dire Wolf shifter to compete with a Level 5 Manticore shifter who has flight and ranged tail spikes.
A Manticore is CR 3
A Dire wolf is CR 1
A CR 3 beast is a Giant Scorpion.
Really, you'd need to create more monsters to get a shifter class to work. That's why only a few have designed it.