ORAC,
No, economically, militarily and in terms of population Russia is in terminal decline.
I cannot comment on the economy, nor population decline however, the Russian Navy is certainly not going downhill. A huge increase in spending is working its way through their system resulting in some excellent new submarines etc, shortly coming into service (well advertised from unclassified sources by the way).
As this post is about Syria, Russian defence material exports are obviously doing well too.