There were no error made in this coin but now there is an initiative to make some changes. Changes are always bad and changes destroy participant confidence even in case these changes are looking as useful. We have to be very careful before making any changes in coins

Also, miners aren't the only stakeholders, and while a miner voting process is great, it isn't the answer to every question. Though I do agree that miners need to be on board with any hard fork to avoid a harmful split.
This is the point. The network that isn't supported by miners is useless. We have to ask them.
Yes I agree with that, as I said. To be fair though, I believe that a large portion of the current hash rate, most likely a clear majority, was active in the meeting where these things were discussed.
I agree. Let's make two separate voting processes.
Merged mining will be turned on only in case 75% of hashpower will be supporting it. For me this is ok. If less we will not introduce it. Is this ok?
For emission schedule modification is 75% a good margin?
75% percent is probably a good margin for miners to approve just about any hard fork. With anything much less than that you are going to end up with a split.
Let's not forget though, non-miners have to approve too.
Do you mean non-miners as a forum users?
Not especially forum users. no. People running nodes that aren't mining still have to validate the blocks, otherwise you get a different kind of split. Or alternately if people don't like what the miners are doing they may simply stop using the coin. Miners are not the only stakeholders in a coin, just one important one.
There will soon be a web site, and other ways of communicating. Now the forum is pretty central, but that will likely not always be the case.
how are you gonna ask all the coin-people? it's impossible and useless.
miners are the main people in the net. 'cause if they don't like the changes and stop mining and supporting the net, coin will die at once. so kinda of "miners referendum" via hashrate power is enough.