fiu-fin-decl woes

I don't want to discourage you too much from your work on inflection templates, but as comes to reconstructed languages, they really should be based on explicit data, preferrably from explicit sources. Also, these should not assume perfect regularity by default. This locks away the ability of other users to actually edit the inflection data in any way.

Case in point — I just removed some clearly wrong instances from PF adjectives ending in (e.g. , , ), where your template insisted on an oblique stem ending in *-oi-. No such thing is attested anywhere. The -oi-/-ei-/-i- alternation in plural stems is only predictable-ish for bisyllabic nominals (and even they have some quirks), not for longer ones. This is probably partly due to analogy, but also due to early vowel reduction of *-a- to *-e- in some inflectional stems (and thence *-aj- > *-ej- > *-i- rather than a diphthong). It is also not immediately clear if the original split was conditioned by the immediately preceding syllable or the stressed syllable.

I've noticed a few other problems come up too. One I can remember off the top of my head is consonant stem formations: just as e-stems ending in a coronal consonant can have consonant-stem partitives, they can also have consonant-stem essives. These have been analogically reverted away in all standard languages, but they are attested in e.g. Finnish and Karelian dialects; lapsi : > > lassa.

The core problem is that no comprehensive reconstruction of Proto-Finnic has been published anywhere, so work on finer details of inflection requires knowing the original research literature and the entire relevant research data — including dialect forms. There is no royal road here.