Translated from a Dutch website:
The original story was written by both Soeteman and Verhoeven shortly after the finishing of the series called 'Floris, which was made in 1969. It was originally called 'the mercenaries' (De Huurlingen in Dutch). It was supposed to be a medieval story about a number of soldiers that are paid to reconquer a city. After reconquering the city, they are betrayed by their leader and have to leave empty-handed. Revenge is supposed to drive them further. The story is inspired by the Siege of Munster in the 16th century and also by the movie The Wild Bunch from 1969. 1
According to that same site, the adaptations that Orion made to the original script are to give the mercenaries a more Anglo-Saxon character and make the setting more continental by changing the Dutch landscape for "Europe". That site doesn't mention Orion wanting a 'love interest'
If you prefer to have an English source:
Verhoeven and co-writer Gerard Soeteman had based the screenplay on an unused idea for their Dutch TV series Floris, the original story concerning two captains at war with each another after one is dismissed in the aftermath of battle. Inspired by Peckinpah’s The Wild Bunch (1969), Verhoeven was attracted, as ever, to the potential of twisting genre inside out – he described the movie as an anti-fairytale to counter the “feigned reality” of King Arthur, and sought to make it decadent and sleazy. A damsel-in-distress love story was foregrounded to placate American financiers, who were no doubt eager to push the film into the fairytale/fantasy realm of Excalibur (1981), Ladyhawke (1985) and Conan the Barbarian (1982).2
Now, back to the Dutch sources. I've found some pages from a book about Paul Verhoeven and the original script of 'the mercenaries' here. It states:
Verhoeven said: The Wild Bunch is a good movie, but it never gets to have a real confrontation between the main characters. We thought we could do that better.
So, the original script all about a serious confrontation between the main characters I guess. Then there's this information about the first scenario of "The Mercenaries":
The first scenario for The Mercenaries includes multiple confrontations between captain De Jonker and sergeant Maarten. When Arnolfini's son Jehan is also captured by the mercenaries, De Jonker comes to a bathhouse to negotiate. He's already in a tub when Maarten enters naked with a bundle of clothes in his hands. He also gets in the bath, both are wary. When Maarten with an unexpected movement grabs for the soap that's slipped into the water a little too obviously, De Jonker pulls out a dagger he put into the wood of the tub, underneath the water, beforehand. As soon as Maarten sees the dagger, he pulls a long knife from his bundle of clothes. Both are sitting across from each other, weapons pulled, brooding. They soon strike a bargain, but that will of course turn out to be false promises soon.
Here, we also find conformation that Orion wanted a love interest into the story:
Orion wanted to work a love story into the plot, to increase the appeal of the movie for the American public. This meant the kidnapped princess Agnes got a key role, contrary to the original storyline. By doing this, the confrontation between De Jonker and Maarten was pushed into the background.
And to finish it, a quote from Verhoeven on the original intent for the film:
A pleasant mix between the western Vera Cruz, the adventure movie The Crimson Pirate, my own Floris and a little bit of Star Wars.