Something similar har been proposed not so long ago with a GB to collect Vicotry and Watchtowers. (Could not find it right now, sorry).
– In any case you will have to adjust your city as you progress – Space is the main challenge of this game and most players never has space enough to place everything that they would like to. Other players leaves space open and theirby looses out on rewards, ranking points, coins supplies etc.
If you want to maintain a lot of passive medal income you should keep your Victory towers – Else you should aim for winning buildings that has a high payout of daily Medals like e.g. the "Caravansary" – Several of the latest Cherry blossom buildings offers daily medals and many others too – Win some of those and remove Victory Towers accordingly.
I would though not advice going for any of the GB´s that offers Medals, at least not choose them for medals first. The Current GB´s that offer Medals in the combo are far far behind the new Event rewards buildings in medal payout and will need a significant amount of FP investments to become worth it.
Last but not least, FoE is a long term based game and there is trickery and traps invovled for the players not paying attention.
– City planning. How to place expansions the best way and how to avoid using too many roads, particular double lane roads.
– Tech Tree Planning. How to prepare for entering a new Era without stalling.
– Killing your darlings. Knowing when to eleiminate buildings that no longer supports your gameplay, Era or level.
– Great Buildings. Knowing what GB´s to choose and which GB´s that are not worth it.
– Fighting Units. Knowing which units and unit combos works best for various Era´s; PvP, GE, Expansion Map and GvG does not work in the exact same ways.
– Play Style. At some point decide what kind of player you are: Fighter, Balanced, Trade/Farmer/support – all play styles requires adjustments to be working well.