There were not 50 arrests. You could count the arrests on the night of on your fingers, and at least part of those were nearby onlookers - not rioters - who "failed to disperse". There were probably 50 who were investigated by the conduct board, and several were sanctioned. Very few were charged and even fewer were convicted. I don't think they got a single felony out of the whole thing.
Statements made to the media in the aftermath, and the resulting stories, inflated the event to something much larger than it was. Some claimed that there were 2,000 people rioting. Pictures never supported that, and the area that it was located makes it even more unlikely. The crowd that rushed the field after the Boise State game was much larger than the "riot". Maybe a couple hundred participants, led by a handful of morons at the core, seems more likely based on the video and still photos that came out after...and there were probably a couple hundred more onlookers who didn't participate. So yes, overblown. Yes, there were injuries, although most of those were minor. Media reports at the time indicate that 18 of 23 responders were treated and released, but subsequent reports have changed the language and now typically say '23 officers were injured'. Technically true, but misleading. Again, overblown.
As for mismanagement, there's really no argument about this. The original incident was at a well-known party house in the heart of greek row...directly across the street from one fraternity, and about halfway between The Coug and what was then Shakers. This house regularly had large parties. At some point, it became a police target. Cops (Pullman, not WSU) would regularly walk by, and whenever someone stepped off the lawn and onto the sidewalk they'd demand ID and write MIP/C or whatever they could justify. It got to the point that the occupants started fencing the yard with tarps whenever they had a party (don't remember if that was pre-riot or post-riot). Anyway, two officers were - according to PPD - called for a pedestrian/vehicle accident at the intersection in front of the house, which apparently didn't happen. According to them, once they got there people at the party started 'pelting them with rocks and beer cans'. I started questioning the story right then, because Pullman isn't known for its abundance of rocks, and this house wasn't xeriscaped in 1998. Anyway, the two cops retreat a few blocks and call for backup.
After that, cops just kept making things worse. They closed the bars and parties, and added a couple hundred more drunk (and now pissed off by the early closure) students to the handful of unrulies already in the street. Then, rather than setting a perimeter and letting the crowd fizzle out on its own, they decided to force them to comply - advancing in formation and launching tear gas. As if that wasn't enough, their path of advance cut off the route home for most of the crowd. And then, their tactics came apart. The group of WSU/Pullman officers ended up driving the crowd right into the County/State group, so the crowd was trapped. Then, somehow the county/state group retreated to the point that they were at the bottom of the hill on Colorado, and the bottom of the hill is hardly ever a good position.
So, let's recap - cops reacted to an incident with a small group in a manner that turned it into a big group. Then they forced a confrontation with the big group, with a simultaneous escalation, and then cornered said group with no way to escape. Yes...mismanaged.
I'm not saying the rioters were in the right, but the incident was poorly managed, and it was (unintentionally) escalated by the police response at virtually every turn. In the 20 years since, it's become the norm to re-tell the story as if it was the LA riots come to Pullman, and it's a miracle nobody was killed. The truth is that it was a couple of hours, some scorched asphalt, and a couple broken windows, and the number of injuries that required even an overnight in the hospital could be counted on your fingers. The articles you linked really don't tell the story, because none of the writers were there. I was. I drove down Colorado Street that morning - just a few hours after the whole affair ended - and there was barely a sign of it. Hardly the riot of the century.