I always have thought that the greatest addition to Smyth would be to add a Koine section to each of Smyth's sections with notes on forms, and syntax, just like he has on Homer. It could be done as a wiki using the current Perseus version as a base. (Any takers?)
How does Smyth line up with Koine? Pretty well. There is about 95% of agreement between Attic and Koine. A list of the main differences can be found in an article by Jay Treat. I keep a Unicode copy at http://www.letsreadgreek.com/resources/treat_classical.html (with his permission). An example of the differences can be seen in the imperfect of εἰμί. This verb changed, and Smyth does not really note the differences. But Smyth does frequently refer to "Late Greek" which I think he intends to refer to the Koine era.
Smyth §768 (Attic)
Sing. 1 ἦ or ἦν
Sing. 2 ἦσθα
Sing. 3 ἦν
Dual 2 ἤστον
Dual 3 ἤστην
Plur. 1 ἦμεν
Plur. 2 ἦτε or ἦστε (rare)
Plur. 3 ἦσαν
Funk §405 (Koine)
Sing. 1 ἤμην
Sing. 2 ἦς, ἦσθα
Sing. 3 ἦν
Dual 2 (not used)
Dual 3 (not used)
Plur. 1 ἦμεν, ἤμεθα
Plur. 2 ἦτε
Plur. 3 ἦσαν
But other than Smyth's lacking presentation of the Koine verb εἰμί, almost all other verbs line up with Koine.
Blass De Brunner is a syntax. It does not contain any charts of forms. Smyth has both forms and Syntax and morphology. No grammar has a more complete review of numbers, relatives,adverbs, adjectives, etc. Smyth glosses all citations with English so the student knows what is intended. Mounce is a first year 'beginners' grammar. It does not cover everything. Funk's grammar (A Beginning-Intermediate Grammar of Hellenistic Greek) is available on the B-Greek website at http://www.ibiblio.org/bgreek/project/funk-grammar/pre-alpha/. Funk covers much more than Mounce, but is still lacking compared to Smyth. Things are changing with the internet. But it used to be that the student was left on his own -- and the place to go to find an answer was Smyth.
Smyth's order of presentation is what should be modeled by any complete grammar. His presentation of the verb is done by verb type (stem type), not by mood like Mounce does. It is a much better and more intuitive book for the student. I have no idea, sometimes, where to look for a verb form in Mounce. I always know where to look in Smyth.
The point that serious English speaking students of ancient Greek need to understand is that IF YOU DO NOT OWN SMYTH, OR DO NOT FREQUENT HIS GRAMMAR (electronic or book form), you are a mildly interested amateur and not really serious about really learning about the language. IMOHO.
