For me personally, DBZ far outweighs the original. There's so much more content, and the fights are much more intense. Plus I loved the cast of Z a lot better, and it's villains as well. I probably feel this way because I saw Z first, but I wasn't a huge fan of Kid Goku, which kind of ruins the first one for me a little.

I feel that DBZ is much better than the original, but that's mainly because Z was what I have seen a lot more and grew up with. In fact, DBZ and DBZ kai are the only ones that I have ever seen, yet I have seen stuff from the original and I feel that many aspects are much better, especially in kai.

I like Z more. It just had more "timeless appeal" and there were more characters who were relevant other than just Goku. 

Well, I don't think it's fair to pick which is "better". It mostly boils down to personal preference. To create a counter-argument to your points: 1. DBZ's  pacing, while indeed somewhat slow, was mostly due to the external influence of the manga not having new material every week, new chapters at most averaging at 14 pages long, input from the writers (Filler) as to not overtake the source material, and the show having a much longer run time than it's predecessor or successors. 2. I'd say the side characters (namely the human ones) weren't that much more important here than in Z. While they helped out sometimes, they were largely used as tournament fodder or only played a supporting role at best, at several points not actually being around to participate in fights (Red Ribbon arc or King Piccolo arc), or being largely inconsequential. 3. Sure Z's fights drag out some, but they most certainly don't last forever (With the obvious exception of Goku vs Freeza, which lasted around 20 episodes). Even if they were quite lengthy, the characters at least had something to do. 4. The tournaments, in my solemn opinion, are not particularly fantastic. The fights, while short and occaisionally interesting, suffer from predictability (Yamcha always loses in the first round, Krillin usually makes it to the second only to lose to the special opponent, and Goku always makes it to the end). The whole tournament dynamic really chews up the plot, as they take up quite a bit of time without accomplishing much (All the tournaments together take up at least 61 episodes, almost half of the show).  DB is quite good, but whether or not it's better than it's successor, is personal opinion.  

Each of the two have there own pluses and minuses, as Dragon Ball is humorous and the minor characters are more active, as you already stated, but it's not just about the tournaments, and about the fights - well, in my opinion - the longer the fight, the better.. More interesting really, as it shows us more of the characters' fighting styles. Dragon Ball is good and funny, and makes more use of the characters, true - and we all have our opinions - but in my opinion, Dragon Ball Z is the better of the two. 

But, again, we all have our interests and opinions, but the fights in Zenkai are what catch my eye over the original.

It's one of the hardest questions I've ever been posed with, I love them both and the only thing I can say is that the Cell Saga and Buu Saga are better than all of Dragon Ball, but most of Dragon Ball is better than the Saiyan, and Freiza Saga.
The beginning of Dragon Ball Z just feels really badly paced, but the magic is where they connect, they connect so well and you get a boost by going from one to the other.
My biggest problems with Dragon Ball Z are that Krillin and Master Roshi do much less, and I prefer snide Krillin over mature Krillin.
On the other hand, Dragon Ball Z is so much more dramatic, and feels like the scope of the series is far greater. Plus Piccolo gets a nice role, and Vegeta is practically a staple of the entire Dragon Ball Universe now.
I absolutely love Toriyama, and Dragon Ball and Z are my favorite Anime's in general.

I definitely enjoy Dragon Ball more than Dragon Ball Z.

Dragon Ball is focused more on humor, adventure, and all the lovable characters while 90% of Dragon Ball Z is focused on fighting.
I feel like Dragon Ball Z is much slower paced, with half a darn season focusing on one fight, while Dragon Ball is more comfortable.
I also like how Dragon Ball is more perverted, light hearted, and immature than Dragon Ball Z.

Each has something that the other lacks, as many have already pointed out, Dragon Ball focuses more on humor and comedy whereas Dragon Ball Z is more concerned with action and fighting. I've seen both of them, but I honestly prefer Dragon Ball Z. It's been a while since I've watched both of them (I actually watched DBZ before DB so that might partially explain why I gravitate  more towards DBZ).

Although I like both of them, I give this one to DBZ because the fighting is more intense and that really seals the deal for me, not to say that Dragon Ball has its own perks that DBZ lacks.

Dragon Ball is more involved in a way. The characters have to travel,often on foot or a vehicle,not fly to find a Dragon Ball and it is usually not easy to find or get. DB is more on exploration,humor,and character driven,whereas DBZ is more action and fight driven. Plus I like it,because you see how the characters were before DBZ. Goku was a strong but simple minded child. Krillin was bullied by the monks. Bulma was a bit of an ego driven brat,but she did care about Goku and Krillin. Yamcha was actually a threat. Master Roshi was actually useful and was portrayed as a master martial artist.

I like Dragon Ball more, it was more funnier than Dragon Ball Z. It was more carefree and the humor is great. In Dragon Ball Z everything is much more serious and and it's more about getting stronger and beating the next strong opponent with your new found saiyan power. But still I love em both, but mostly I watch Dragon Ball more nowadays. That new Dragon Ball Super it's like huge filler where they just want to ruin the whole series with these red, blue, pink hair new saiyan forms and what else. And the story sucks too much I had hopes they would honor the old series even a little, but i was wrong. It's funny that I like watching Dragon Ball GT sometimes even though it sucks mostly, but I guess it's nice to see Goku as a kid again doing his goofy things.