There are multiple ways to make the game harder.
But, as someone pointed out earlier, it's about finding a sweet spot between difficulty and fun.
Making upgrade times longer and reducing workers might not be in the best interests of the game. Here's why:
1. There need to be reasons for players to login to the game frequently, and to play the game. It's part of keeping the players hooked to the game. Increasing upgrade duration and reducing the number of workers would reduce the need for players to login to the game frequently.
2. Typically, people who play games allocate or plan for a certain amount of time towards gaming. The key is to maximize that share of time for a game, if the game wants to be successful. If upgrades take longer and there's less to do in a game, that share of gaming time gets allocated to other games.
3. Getting people to play a game is part of capitalizing on the habit loop that people form from playing a game. This is another reason why a gaming company should want its players to login and play the game daily, so that they stay hooked to this habit loop.
4. It's important to consider that the time which people devote to games is typically what people consider as entertainment time. It's discretionary in nature. Given that it's discretionary time, it's important to offer entertainment value from the time people spend on playing the game.
It's for these reasons why offense needs to be slightly overpowered than defense. People gain entertainment value when they attack and play the game actively, that is, when they are online. Not so much when they are offline, and aren't playing the game, when they defend. But, this is an entirely different discussion altogether. We can park this for now.
Losing a higher percentage of resources when attacked might encourage players to login more frequently, and to play more actively, and not stay offline for too long for fear of losing the resources. So, that might not be too bad a thing for the game.
Doubling cost of walls would affect everyone equally, so, it should probably not matter too much. In fact, since it'll make defense less attractive and less viable, it's probably better for the game.
Apart from these, there are other ways to make the game more challenging for skilled players. Climbing on the medal leaderboard is probably one of them, without having to make the game harder than it is now.
So, overall, mixed thoughts about your proposal, and I've explained the reasons for the same.
Cheers, and happy gaming!
