In a word? No.
All of your negative points are valid. Add to that wage compression, which is very tangible these days.
I guess I'll have a stab at analysing the positives...
Enrichment of diverse culture. This can be good, but it just isn't in the volume we see it today. This process takes decades, as it has in the past. The migration of people from all over the Empire, and later the Commonwealth, was slow, limited, and took place over generations. Their cultural traits gradually melded into our own, to form what we call British today. Since 1997, and particularly 2004, we've seen a sharp increase in net migration in a very short amount of time. There has been no time for immigrants to adapt. Instead, they've fragmented into, as you listed above, ghetto-like communities, with no desire to integrate. There is currently no practical reason to integrate. As an immigrant, you can exist perfectly well within your own social circles, with friends or state-sponsored translators at the ready should you ever need to sort something out in English. This is a non-argument, in my opinion, as for enrichment to take place, you must have integration first, right? There is also a difference between gradual enrichment and the sudden introduction of (sometimes) vastly different, immediately incompatible cultures. Forced multiculturalism will never work.
Filling in genuine skill gaps. There is a huge grey area here, and cannot be argued successfully by either the pro or anti-(European)immigration movements. Yes and no is as close as either will get. However, on the whole, logic favours the anti stance. Yes, there is a skill shortage in very specialised fields (mostly medical), but for most things, we already have the necessary skill set. The question for employers is pay. Immigrants simply have lower expectations when it comes to pay, and are perfectly happy to work for less. Any of you reading this ever been to an Eastern European country? Well, you can live very comfortably there on money which wouldn't buy much here. This leads to British people being slowly priced out of the jobs market. The average wage isn't rising below inflation because the economy is still struggling; the main problem is overpopulation, which allows for more low-mid skilled jobs have lower pay attached to them.
Individuals who give a lot to local communities. This has nothing to do with immigration. Pillars of communities were already present, and it is ludicrous to suggest that immigration is necessary to have figureheads like this at a local level. If anything, the trend is that migrants keep to themselves. Only with 2nd/3rd generation immigrants do we see more community engagement, but even then...not really. Community leaders are on the decline, for both good and bad reasons. As for things like community efforts, migrants rarely engage in these either, as they are not invested into the community in the same way that someone who grew up there is. It is far more likely that someone who was born in a community would want to help better it than someone who moved there (often) temporarily. This is also a non-argument, in my opinion. I live in a community with plenty of migrants, and I can tell you..they don't do anything to benefit the larger community whatsoever.
Individuals who introduce effective, foreign derived initiative to our industries. Again, yes and no. While there is expertise and problem solving that is valuable from outside the UK, do we really need mass immigration for this? No. There are people paid to improve industry already. The average migrant worked has nothing to say in his workplace, either because it's already as efficient as practically possible, or because he doesn't know, or because he doesn't care. Besides, we are the UK. One of the most forward countries in the world in terms of problem solving. We already have expertise and foreign trade links. Foreign business are lining up to trade with us, we don't need to go looking for them. Non-argument again.
Your bottom point hits the nail on the head. High level immigration directly benefits big business and corporations. Almost nobody else. Anybody who says otherwise is either in the 'almost' section of the population, or has hardline political ideas impermeable to logic and real-world statistics. It's all very well bouncing figures off the walls, but these figures are often manipulated anyway. I doubt they take things such as overseas child benefit, for example, into account. Even assuming they're not, you're right in stating that there's more to the issue of immigration than just a number. £20bn is spitting in a bucket for the UK economy anyway. And if it doesn't benefit the public, it cannot be seen as a net benefit to the UK.