An important point to consider when thinking about Traveller naval doctrines is that of sustainability. With a wide variance in local tech levels between worlds, and with the long transit times from world to world (a week per jump), in many cases warships in need of repairs, maintainance or replacement of small crafts will have to go over quite a distance - and waste precious time in transit - to get to a world with a good starport and high enough TL. Lower-tech ships will be able to find repairs on more worlds, especially near the frontier. On the other hand, navies will want to have the highest possible tech on their ships. So a balance should be struck between the need to have the most sophisticated fleet in the region and the logistical needs of that fleet.
Another related matter is that of production. In a polity where high-tech worlds are rare, producing most of the fleet on these worlds will limit the speed and capacity of fleet production, and will be vulnerable to deep-penetarting raids against the producing worlds (especially if the polity is small and thus its border is relatively close to its core).
Both of these probelms won't be very significant if the polity is large and well-developed (like most Classical Era OTU polities), but with smaller and less developed polities this will be an important point to consider, especially when considering the need to supply and maintain fleets deep in enemy territory.
Another related matter is that of production. In a polity where high-tech worlds are rare, producing most of the fleet on these worlds will limit the speed and capacity of fleet production, and will be vulnerable to deep-penetarting raids against the producing worlds (especially if the polity is small and thus its border is relatively close to its core).
Both of these probelms won't be very significant if the polity is large and well-developed (like most Classical Era OTU polities), but with smaller and less developed polities this will be an important point to consider, especially when considering the need to supply and maintain fleets deep in enemy territory.