The solution I offered is to add links between the navies and continents. The Punic War example was to show that such links make historical sense.
As for Trajan, he waged wars agains the Dacians and the Parthians. But I presume that the map has links between area that *could* be attacked given contemporary military technology, not between areas actually engaged in warfare uring Trajan's reign - because in the latter case you'd have almost no links at all..
YOu offered solution to improve what. These map dont have continents, and people must have some part of territory to hold,and you have several examples
Baetica-Arabia petraea
Syria-Asia-Bithynia et Pontus
Italia-Praetorian guards and roma
Lugdunensis-Belgica Britannai
Dalmatia Panonia-Thracia Macedonia
Baetica-Taraconensis
Conection betwen africa and sicilia you will brake holding sheme for africa and split on two, and still not get nothing good.
Historicaly i realy research (these people kow here that i so many hours spend on researh,because i create historical map-Eastern Front-Western Front-Ardennes Offensive-Iwo JIma BAttle) and i try to be as much possible historical correct. These map is how tittle say Imperium Romanum 117 AD,when empire whas in bigest extend,and in these years Romans whas very peaseful place for live(i think so).
OFcourse you have many other scenarios here-Punic wars map(RubbenCasaar) Roman empire Decline map(i dont know who present that) Buzantine Empire(abandonen) and many others.