It takes hours to confirm a transaction so it can be better like other coins to process faster.
[IMO]
Faster transaction = Less secure
Slower transaction = More secure
I'm wondering, how to solve this problem without making any problem even worse.
you simply do not solve it, because it isn't a problem, merchants should just go ahead and accept 0 confirmations
but if you really want a solution sidechain are what you are looking for
0 confirmations should be enough, but accidents can happen like the one we saw yesterday, where the blockchain split happened.
We need these to be solved before we can have mainstream adoption and merchants being careless about confirmations.