Are verbs in Lojban broken?
It looks like it would be difficult to learn such definitions of verbs like
x1 runs on surface x2 using limbs x3 with gait x4
English is pragmatically the same. It has verbs with their implied place structure. The only difference is that Lojban dictionaries don't cheat whereas most English dictionaries hide such place structure.
The reason behind such system is that having a separate preposition denoting each place would be even more tiresome and sometimes even unusable. Imagine:
I depend to you (?!)
I depend on you
I depend from you
Also note that most verbs in Lojban have up to three places only. Only ~30 core verbs (lo gismu) have 5 places. And you don't need to know every place of every core verb to be able to speak fluent Lojban. Indeed, is it really important to know the place structure of 'trigonometric sine function' when you are going to talk about preparing food?
It's true that "I give you a present" doesn't require prepositions while place structures of other verbs do require them. There isn't more memorization. English requires you to learn metaphors. Why "I give TO you" and "I talk TO you"? Why "to" both times despite completely different processes here?
I think of you
Ya dumayu o tebe
I think about you
Yo pienso en ti
I think in/into you
This happens in English too all the time. Why "This movie is pleasing to me" but ... "I like this movie"?
Also note that verbs in Lojban as in English can be grouped into frames with identical place structure, e.g.
x1 is a cat of species x2
x1 is a dog of species x2
Place structure is easy to learn but ...
Often the place structure is easy to learn. However, the concept of movement has a random set of place structures. Look at this:
x1 (object) moves to destination / receiver x2 [away] from origin x3 over path / route x4.
x1 runs on surface x2 using limbs x3 with gait x4.
A person using a treadmill doesn't have any "to" or "from" points but is simply running while staying at the same place. I think this is a good example of bajra state while not being in klama state.
In short, Lojban is not a relexed Engish, although common usage and Lojban-English dictionary might suggest that.
It is a problem of English's ambiguity than something to do with Lojban language.
Finally one can employ lo tanru like bajra klama (to run-come) to express both running and coming to some place.