organ guns are strong but expensive and really Only good in cadtle age. They die horribly to paladins or mass hussars in lategame or siege onagers wipe the floor with them.
If you got good micro you can use BBC against SO and siege rams but for the average bad player a sudden SO shot can ruin you.
Siege rams are the bane of Portuguese. They donāt have any FU meele unit. Even thought their units are cheaper, they are just not strong and get pushed back.
Since they got not a single good combat bonus (arqebus isnāt really great other than for BBC). Only their archers are even FU.
There real strength is out lasting the enemy with the gold discount but until then they often lose fights due to generally weaker millitary units (except organ guns but see points above for that) so the ports often get pushed off the map and their early game has nothing going for them either.
Portuguese are bad early game and arenāt overwhelmingly strong in imperial age. A jack of all trades, good for nothing approach doesnāt work in aoe2. It is better to have super cheap cav (berbers) or super cheap archers (mayans) and use the bonus to its fullest then get a mediocre mix of these.
You can either try to be a weak berbers or weak mayan, or the ports tries to go both, needs so many upgrades and just loss to the enemy focusing on the one thing they are great at.
The best ports have is propably their monks mangonel push working really well for them. But a civ with a proper eco bonus helping earlier would be almost as good and more flexible.
I would argue that Portuguese need to be better at imp to off set that they are so bad early game somewhat. So an aquebus buff, hc buff and elite organ guns +1 range or more aoe.
Or feitorias changed into a proper imp eco bonus (no Pop cost but limited by fix amount like cuman tc in feudal)
If we buff their eco ealry game slightly , then we end up with a civ that is Stil not amazing early game and still not great in imp (Jack of all trade problem and not much FU, mongol deathball kills them easily for example).