Yeah i know it's a hardcoded problem that the AI will always attack the human, especially the grey monster who will ALWAYS attack you if you share a border with them.

As this is the case, do you not think it might be fair and justified to add two or three more units to Pontus' starting army, say an extra unit of slingers, an extra unit of levy phalangites and maybe 1 single unit of at least mid-range, decent infantry, as well as some extra population to the capital city and a little more infrastructure?

Even if you do this the faction is still going to go into debt immediately and it's still going to be a hell of a long time before you can recruit any new infantry, so it wouldn't be tipping the balance in your favour, merely giving you a fighting chance.