I've been using SwiftKey for quite a while now. I'm missing a couple of features in my native language (Greek) so I'll go ahead and describe them:

First of all, when using the greek symbol for question mark (;), the next word should star with a capital, as is the case in English. This doesn't happen in latest SwiftKey version.

The second issue is about the greek vowels and their punctuation. In the default Android keyboard when a greek vowel is long-pressed then the selected letter is by default the same punctuated letter. In SwiftKey, the default behaviour is for a symbol to appear, for example in long press α the symbol @ appears, in long press η the symbol + appears, etc.
So it should be like this:

Caps
Ε (long press) Έ
Υ (long press) Ύ
Ι (long press) Ί
Ο (long press) Ό
Α (long press) Ά
Η (long press) Ή
Ω (long press) Ώ

Lower-case
ε (long press) έ
υ (long press) ύ
ι (long press) ί
ο (long press) ό
α (long press) ά
η (long press) ή
ω (long press) ώ