As far as I see, this is actually the intended behaviour. Remember, "tall" must be competitive with "wide", and this means the "tall" provinces should be much much better than "wide" ones.
Why though?
Don't ask me, I too consider the idea that small countries should be competitive with big ones for no apparent reason as dumb as hell, but it's a pretty popular meme among current strategy gaming scene (just google "tall vs wide" to see the extent of the problem) and it's going to be forced on us until it dies off.
I suppose one good example would be Germany vs the great blobs of the USSR and the British Empire, which is as small vs blobby as you can get. Even still that one was about a small nation having an advantage but deeming being blobby as necessary for its continued power. I could see some value in at least having momentary advantages over expanding nations... Until they finish expanding.
On that note my Nepal Empire run has entered a very interesting stage; the Roman Empire collapsed.
The Austrians, Saxons, Huns and Sarmatians were the first to invade the Roman Empire, the Romans could have held off longer if the Greeks and Persians had not also attacked and destroyed their Arab vassal. The Iberian peninsula held on for longer for it was infested with animist rebels, eventually it too fell to the Germanic hordes. With most of Europe in a state of fucked or soon to be fucked, Emperor Vitellius Ostorius made the bold move to move the capital from Rome to Alexandria at the age of 16; shortly before Germanic pagans sacked Rome. North Africa was quite Roman, with an exception to the Western half which had been taken over by a great Berber tribe. Emperor Vitellius was an absolute genius in all fields of governance, including the all important military strategy. There was hope for Rome. For many years the resistance in Alexandria held out against unbeatable odds, not least of all because the Romans found an unusual ally.
Emperor Rajandralakshmi Chola of the Nepalese Empire sent 26,000 swordsmen and 8,000 war elephants to Alexandria and crushed the various rebels plaguing the last of the Roman Empire. When the Saxons first hit North Africa the Nepalese and Roman forces fought bloodily to the last man, losing much of North Africa but keeping Egypt safe. In the second war Rajandralakshmi sent another 32,000 swordsmen and 10,000 war elephants - this time the Saxons were only stopped at Egypt itself, with the last Roman Legion of Nepal
holding the Suez. After the third war Rajandralakshmi withdrew the only surviving units back to India, the 2nd Rome Legion and another amalgamation of units who did not survive in full strength or never made it to Egypt in time; once the Suez fell there would be no way to bring Nepalese soldiers home.
The alliance was dissolved and a heartbroken Emperor Vitellius died. The Saxons pillaged Egypt and the Berbers invaded Corsica, what surviving remnants of the Romans departed for Jerusalem and Damascus where they were outnumbered by the Chalcedonians who they had previously successfully suppressed. The Hellenistic Greeks to the North began eyeing the last pickings of their old foe with relish.
Rajandralakshmi would shed no tears for Rome (though his Roman wife did), as the Parthian Empire launched a fullscale war against the Nepalese Empire to prevent it from taking over the last independent states in India. The Persians, their nomadic allies and their coalition had superior soldiers, technology, tactics and commanders. The Nepalese Empire and their ally the Han Empire had the advantage of numbers. 250,000 Persians up against 500,000 Nepalese, Chinese, Bengali, Afghan and Tibetan soldiers, fighting the bloodiest battles the world had ever seen since the fall of Rome.
The Gauls are the most powerful force on the planet, but they are yet to surpass Parthia or Nepal in terms of diplomacy, culture or trade. England is ahistorically powerful, having united all of the isles. The northern hordes are best left alone, and I may try to fix that broken mess that is the Han Empire... Though it is also tempting to try and destroy the Parthian Empire and cut my way to Jerusalem to try and save a little Roman Empire. How entertaining it would be to try and make Hinduropa with Roman cores!
The Gauls have spread the Germanic religion far and wide, wiping out much of the Hellenistic world (which in turn had been successfully suppressing Chalcedonism). Hinduism has nearly taken over all of the Indian subcontinent, with a few Zoroastrian leftovers being converted. After some great internal turmoil between Confucian and Buddhist rebels, the Buddhist rebels finally defeated the Confucians and so now the Han state is Buddhist whilst the Zhou remain Confucian, furthering their divide. England is also still druidic, as the Chalcedons did not arrive before England became independent from Rome.
Germanic culture has swept through much of Europe, erasing what the Romans have done. Persians are steadily blobbing through Arabia and Mesopotamia just as Nepalis have blobbed through India, though other Indians in the Eastern Aryan group also make up a significant portion of the Nepalese Empire. The Greeks are protecting many of the Romans, Illyrians and Dacians who escaped the barbarian invasions. Of note is the strip of Tibetans on the outside of the Nepalese blob, soon they will be a buffer state with East Asia (and soon, potentially conquerors of East Asia)