Wow, how much the OP has to learn. When GBG can give more than 1000 fp each day for an advanced player, and likely at least 12 fp for a low level player who participates to a reasonable degree, with most players falling somewhere in between, the tavern pales in comparison for fp production. Where the tavern shines is in the 24 hour 30% attack boost, and that is used to make GE and GBG even better. GE gives decent fp and troop rewards for low to average players, but where it shines is in diamond rewards. They all have their place.
As to the OP's list... you cannot get blueprints from your tavern. City shield is a complete waste of tavern silver and is for those who don't know how to play, and think loosing a few supplies or coins is a big deal (or even a few fp). Shorten build time and recruiting time is another waste of tavern silver, join a good guild and get a better boost for free. Coin and supply boost are great for fulfilling event quests cheaply, otherwise they pale in comparison to other ways to boost those items. Other than Attack boost, the only other really useful one was completely missed by the OP (but mentioned by Nicholas above) - Extra turn for GE - if you can't battle all the way to the end of level 4 in GE, you can use the boost to negotiate easily to the end and win all those great level 4 rewards. Not occupying space is great, but is your city completely optimized to the point that it really matters?
More functions doesn't necessarily make something more useful. I wish I had more uses for my millions of tavern silver.
And yes, GE is now a building - Look for the 3 mast ship - as are GBG and the settlements above and below.