Well, they are common gym types.  I don't believe we'll get another new type as we already had one recently and whenever types get added, a new Eeveelution is added and a gym will have the newly-added type.  Beyond the original three Eeveelutions, new ones have been added in the even-numbered generations.

For what I predict, we'll get at least 130 new Pokémon (including Magearna) and few (if any) new mechanics since we're going into an odd-numbered generation.  My logic can be broken down as follows:[list]
[*]Generation I (The Colour Generation):[list]
[*]The cornerstone of the franchise with 151 Pokémon
[/list]
[*]Generation II (The Metal Generation):[list]
[*]100 new Pokémon including two new Eeveelutions and new pre/post-evolutions of existing Pokémon
[*]Genders for most Pokémon (outside of the Nidoran evolution line)
[*]The Dark and Steel types
[*]Proper STAB moves for the Dragon type
[*]Happiness as a mechanic
[*]Multi-form Pokémon
[*]Time sensitive events
[/list]
[*]Generation III (The Gemstone Generation):[list]
[*]135 new Pokémon with new, but fewer pre/post-evolutions of existing Pokémon
[*]Special abilities
[*]Double battles (the anime showed a few precursors of this mechanic)
[*]Pokémon Contests
[*]The first re-releases of old games with current-generation battle mechanics
[/list]
[*]Generation IV:[list]
[*]107 new Pokémon including two new Eeveelutions and new pre/post-evolutions of existing Pokémon (the most yet)
[*]The Physical/Special split (changing the paradigm of battles from there on)
[/list]
[*]Generation V:[list]
[*]156 new Pokémon (the most introduced so far)
[*]Hidden abilities
[*]Trading and battling over Wi-Fi
[*]Region maps no longer showing orthogonal routes
[*]Triple battles
[*]Rotation battles
[*]Inverse battles
[*]Two sequel games instead of one
[/list]
[*]Generation VI:[list]
[*]72 new Pokémon including one new Eeveelution (the fewest yet)
[*]The Fairy type
[*]Affection (or bonding) as a new mechanic
[*]Mega Evolution, causing a power creep
[*]Primal Reversion
[*]Sky battles
[*]No sequel games (we expected a [i]Pokémon Z[/i] after [i]Corocoro[/i] revealed the new Zygarde forms) :arghfist
[/list][/list]

I've grown to like the new starters with the possible exception of Popplio—I consider it similar to Oshawott.  Owlett is so darn cute and Litten looks like it doesn't care in the slightest (that's in a category of cool).