tener ganas de in different tenses

Question

In the lesson you give examples for estar deseando in imperfect, but not for tener ganas de. I feel pretty sure I could use tener ganas de in imperfect as well, but neither seems to fit well with preterite.

Could you say more about how these two are used with other moods and tenses and what limitations, if any, exist.

EDIT: Sorry, I see you answered part of this in an earlier reply. However, could you indicate any other limitations that might apply. I wonder about subjunctive too.

Answer

Hola Graeme,
In terms of limitations on some indicative tenses, apart from what has already been mentioned about the preterite (unusual use), I would say that progressive tenses are not used with tener ganas, probably because it is more of a "static expression" as opposed to a dynamic verb. Verbs that express emotions don't tend to use progressive tenses; it would be very weird to say:

Estoy teniendo ganas de ver una película.  ???
¿Estabas teniendo ganas de verme?  ???

With "estar deseando" however, we will always have progressive tenses. As you can see, the structure itself is estar + gerund. 
The subjunctive can be used with both tener ganas or estar deseando, for example:

Estaría bien que tuvieras ganas de verme más a menudo.
It'd be good that (if) you felt like seeing me more often.
No me extraña que estés deseando ver a Juan. Ha estado fuera dos meses.
I am not surprised that you are looking forward to seeing Juan. He's been away for two months.

Saludos,
Inma