Comparing to Free Greek, "Latino sine flexione" has no particles to denote past and future and tenses in general, while Free Greek has e- for past, tha- for future, mía for the "once" aspect of verb, and the auxiliary 'ekhei' for completed action. It would be a good idea to use suffix -turo for future participle, which might also be used without 'es' (to be); i.e., every participle should also be used as a verb.
Further, "Latino sine flexione" has only one way (preposition 'de') to denote the genitive, while in Free Greek there are unlimited means to substitute the genitive; any preposition or other affix (besides the most common 'apo', 'ap') can serve the purpose depending on the exact purpose of genitive, also we have the possibilities of dropping the noun's final vowel, using postposition instead of preposition, using simply the word order (optionally combined with vowel stress) to make a compound, creating an adjective with ending -ítiqo in place of genitive, or placing the modifing noun without suffix followed by the modified with a 'genitive' pronoun (e.g. 'paidí - synaístheemas-at' = the child - his/her feelings = the feelings of the child). LSF should adopt analogous means.
"Latino sine flexione" must have an absolutely strict word order, while it can be as free as possible in Free Greek. In "Latino sine flexione" there is no marker of the verb object, whereas Free Greek can use -n for this purpose. For LSF i suggest the addition of –m for object preceding the verb.
"Latino sine flexione" can only show the passive voice by periphrasis - in Free Greek there is the suffix -etai. It would be a good idea to use the passive participle of LSF without the auxiliary 'es' (is, are, etc.), as 'es' can be ommitted as usually in Free Greek. (Every participle should also be used as a verb in LSF).
"Latino sine flexione" is too cumbersome in forming adverbs by periphrasis "in modo ...", "in mente ...", whereas Free Greek uses -(t)a. I suggest the addition of suffix -ter for LSF.
In general "Latino sine flexione" could be much better by imitating the ways of Free Gree as i have described it.
The purpose of Free Greek Language is not primarily for making Greek an international language - although it is also common sense that only in the Free form Greek may ever become international. Free Greek Language is primarily to save Greek Language from extinction among speakers who live outside Greece or visit Greece; it is to make Greek language no more hated and abandoned or misused because of its useless perplexity; it is to make Greek language really lovable and able to grammatically and syntactically express with utmost ease anything that any language can express. It is to become official language in a future aspired Greece that would comprise nations of different languages. And it is for all purpose that a constructed language can serve http://en.wikipedia.org/wiki/Constructed