The United Kingdom is already punching well above its weight in the world, we are already a small union, a small player in Europe and in the world. Scotland leaving would create two new entities each of which will have even less influence on world affairs than the UK has now / had before.
The other aspect is to do with international harmony. In times gone by war frequently raged between England and Scotland, also within Europe war was a regular occurance. The Unions we have created, the UK and the EU have established extended periods of peace. Maintaining these unions maintains the peace. Splitting them up is a move away from continued peace and therefore a bad idea. So, no 'more' just answer that first please.
And there is more ..