Town Hall 8 - Unbalanced Gold/Elixir spending before wall upgrades.
Upgrading from a fully upgraded Town Hall 7 base to a fully upgraded Town Hall 8 base at the moment costs about 67 million elixir and approximately 239 million gold. This means that if you are a player that wants to max out everything before moving onto Town Hall 9; it currently costs you approximately 3.6 times more the amount of Gold than it does in Elixir, which means that most players have to either waste elixir in raids or let other players steal their significant excess of elixir.
This is because Town Hall 8 is the first time that Gold Upgrade Costs (not including Wall upgrades) are higher than the Elixir Upgrade Costs. Its about 110 million gold for non-wall Gold upgrades and 67 million elixir for elixir upgrades.
This equates to a fraction of gold to elixir that is 110/67 = 1.64. Comparing this to Town Hall 7 and any town hall before Town Hall 8, this number is always a fraction which is less than 1, because the gold costs are always less than the elixir costs before any wall upgrades.
Town Hall 9 and Town Hall 10 used to have the same issue as Town Hall 8 has with excessive gold upgrade spending compared to elixir upgrade spending before any wall upgrades, except Supercell introduced elixir wall upgrades for walls levels 7 and above to try and balance this excessive spending.
However, this did not work as it was too easy to upgrade level 7 walls at Town Hall 7 as the cost of non-wall gold upgrades at Town Hall 7 is still lower than the Elixir upgrade costs. So as most players know, Supercell removed this ability for walls level 7 and 8 to try and balance it, but this removal was too much as it has brought back the issue for Town Hall 8, which now has a unbalanced gold/elixir spending ratio again.
So to fix this issue, Supercell needs to bring back elixir upgrades for level 8 walls, as it is unfair at the moment. If this cannot be done, then Supercell should possibly remove elixir wall upgrades for level 9 to 11 walls again, to make the game fair again.
All gold/elixir costs taken from: http://clashofclans.wikia.com/wiki/Cumulative_Costs