Latins hasn't influenced the languages much, apart from being an acenstor to the Roman languages (with French having a healthy dose of German influence by way of the Franks). The names for grammatical features are from Latin because the Romans thought about their language, and up until humanistic thought people had some sort of inferiority complex about their languages compared to Latin, which is doubly funny when you realize that the Romans had exactly the same inferiority complex regarding Greek. As a result, the corset of grammatical terminology doesn't really fit the more modern Indo-European languages that well anymore.

It has also led to such idiotic rules as 'an English sentence should not end in a preposition', which is, to paraphrase a quote generally attributed to Churchill, something up with which we shouldn't put. But such rules don't take, they get forgotten quickly.

All Indo-Euoprean languages lose inflection, and you are right that pronouns, if used consequently, make conjugation irrelevant. Among the Germanic languages, only Icelandic is more conservative than German. But when you think of it, a pronoun as a separate word before the verb isn't much different from a separate ending after the word. Glue it to the word in writing and conjugation is something which moves from the suffix to the prefix, that's all.

Not having to use a pronoun because the verb form is clear without it could be considered a feature, too.

Robin