I agree. Bigger ships = less challenge = easier game = less fun. I've been on since beginning of PB - over a year - and have no desire to fly/own all the big ships.
On the contrary, the only challenge I've gotten from the game has been revolved around trying to get a bigger, more expensive, but not necessarily more capable ship.
The fun I've gotten from the game has come from operating at the very limits of my credit balance, whatever that may be at the time. This meant investing everything I had in my ship, its outfitting, cargo and one or two rounds of insurance (most of the time). If I had a lot of pocket change but not yet enough to move to a bigger hull like some sort of profit-driven hermit crab, I'd go and buy as many of the smaller ships I previously owned as I could, and have some fun wrecking things in them before selling the whole fleet when it was time for an upgrade.
This has added an ebb and flow of tension and cockiness throughout my career, as I build up one ship to peak performance as my confidence in my ability to handle it grows, then essentially start anew with a huge (to me), unfamiliar, D-grade ship that makes me watch the scanner like a hawk every time I sneak it out of the letterbox. This reached peak tension when I traded in my Python worth 130 million credits to afford the basic, stripped out Anaconda hull at one of Li Yong Rui's discounted starports. I was left with enough change to buy a Viper, C-grade internals, 4 pulse lasers and 20,000cr worth of insurance money. I dared not touch the Anaconda, the physical manifestation of my entire career's worth of accomplishments before I worked up the insurance for it.
Well, until I got bored trying to grind 6.5 million credits in a half-kitted Viper anyway. Then it was a wondrous, heart-attack inducing stint of insurance-less trading with half a cargo hold full of rare earth metals in a ship I'd never flown before with barely enough money in it to get it off the landing pad under its own power.
Bigger ships aren't less challenge if you play them like a bigger and bigger risk to test your mettle.
Oh, and I'm glad to say I was able to make enough to take the Anaconda into its first trial-by-fire at a nav beacon the other day, insurance and everything. She's a fine ship, aye, and with stories to tell from the day her first planks were set down.
My next goal is to acquire and outfit every ship in the game. I just hope that by the time I'm done I'll have a lot of stuff to do in each and every one of them.