After close to 25 years in ATM, if I had received one Euro every time I'd heard how complex, specific, different, and special the needs of any ANSPs are, I would not be writing this email but instead chilling out on a sunny beach in Southeast Asia.
At least half of the time, these words phrases and arguments are used to explain why some new system or change can't work 'here', wherever 'here' might be. This kind of reaction is as universal as the rules of the air defined by ICAO. Every ANSP, every unit, every control center, and every tower seems to be different enough to make systems and procedures used elsewhere not applicable.
This makes engineering and sales hard. But how do we deal with that? The most important thing to keep in mind is that the reality of the feeling has little to do with the reality of its cause. If a potential customer of yours feels that their airspace or operation is the most complex, specific, different or special, there is little sense in arguing against it.
Firstly, as a salesperson from outside their organisation, you have very little chance of convincing them. Secondly, even if their problem is only perceived, it does not make their feelings different. Instead of trying to convince them that their issue is not what it seems, put your effort into showing how you can improve the situation and why what you offer can help.
Don't be the salesperson who doesn't understand or neglects the issue at hand. If you are, you won't be the one solving it. Selling is about listening after all, isn't it?
Vincent