Salvete Amici Amicaeque!
Quaestionem habeo:
Quid est mos melior latine dicerndi “If only it were so.”
Fortasse “si modo sic esset?”
Valete!
hi, i would use VTINAM plus imperfect subjunctive. see woodcock pgs 88-89, s116 (in particular at the top of pg 89, paragraph (b) (referring to the present)):
http://books.google.fr/books?id=WmT6mS5v4dAC&pg=PA88
cicero said something very close to your sentence above (“QVOD VTINAM ITA ESSET!”) in his letter to atticus in book 11, letter 12, s3:
http://books.google.fr/books?id=fcurWFgaTXcC&pg=PA36
cheers, chad 
I might also suggest using a gerund for your question.
‘quid est mos melior dicendi Latine…’
The use of the infinitive seems a bit off to me…
I know that’s nothing to do with your query, but it might help nonetheless.
BTW I agree with cb about utinam.