As listed by Mario With Lazers on Page #115, Pokemon Games following Generations with exclusively Native Pokemon tend to introduce less Pokemon. This pattern has been followed since Gen. I's transition into II, and continued since III's transition into IV. Today, we have Gen. VI, which follows V- which, according to the pattern, introduces less Pokemon that compliment the previous Generations.
For example, Mario With Lazers listed that only 81 Pokemon were introduced in Gen. II, only 11 off of the predicted 70. Also, we see that Gen. IV only introduced 78, closer to the predicted 70 by 3; even that Generation was watered down heavily by Evolutions to previous Pokemon and a large amount of Legendarys.
So in conclusion, Gen. VI isn't a let down in terms of the amount of Pokemon it introduces, as it follows the pattern of previous beloved Generations such as Gen. II and IV, with only small differences; and that's not including the new Mega Evolutions. So that being said, I wouldn't criticize Gen. VI for introducing only 70 Pokes. I would criticize the fact that the Goomy Evo is still only Dragon :/
EDIT: My bad I said "Mario With Fat Lazers by accident LOL